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General Category => Projects => Topic started by: casal-fan on May 04, 2014, 07:01:58 PM

Title: 3MA trackbike project
Post by: casal-fan on May 04, 2014, 07:01:58 PM
I kind of missed youguys, after I sold my 3XV.
Had to do something about it :), so I got meself a 3MA.
Hoppefully, next year, the tracks will be terrorised by the roar of the mighty 3MA ;D
Besides that it has the cylinders turn the wrong way arround (or maybe its the right way arround some would say), I know practically nothing about the 3MA.
This particular bike, I haven´t seen it yet, but the mate that picked it up for me, reports that it sounds very good engine wise, and looks good, without signs of crahes or negligence.
Need4speed, do you know something about it? Got it in Bjerringbro.
It will be an interesting project, that I´m sure about. Time to start reading...



Title: Re: 3MA trackbike project
Post by: maccas on May 04, 2014, 07:27:27 PM
Rui!

Good to have you back! If it's anything like your 3xv project it will be awesome!

Good luck with it!

Dan
Title: Re: 3MA trackbike project
Post by: Need4speed on May 04, 2014, 08:28:18 PM
no dont know it..
Title: Re: 3MA trackbike project
Post by: ybk on May 05, 2014, 02:27:41 PM
Welcome back  ;D That looks like a nice base to start with 8) Do you know how your old 3xv is doing..
Title: Re: 3MA trackbike project
Post by: Louis on May 05, 2014, 07:25:24 PM
Great looking start, You will love it 8)
Title: Re: 3MA trackbike project
Post by: Edd on May 06, 2014, 07:42:10 AM
Hi;

Just for the record all other motorcycles cylinders are the wrong way around >:D Only the 3ma is correct dont understand why nobody ever noticed. You are going to enjoy this build ;) Busy negotiating to buy two basket cases for R4000 about 400 Euro I am addicted cant stop fixing them up.

Edd
Title: Re: 3MA trackbike project
Post by: 41juergen on May 06, 2014, 01:41:06 PM
Hi Rui,

just enjoy, and may be get a bit crazy when fiddling around with the carbs...  >:D

Or do you want hold it stock as possible? :D

Juergen
Title: Re: 3MA trackbike project
Post by: casal-fan on May 06, 2014, 09:18:10 PM

I still haven´t seen the bike. It´s at a friends garage, and I´ll probably pick it up on in couple of weeks or so.
I had to take it out of the sellers hands as quickly as possible, otherwise it would have been gone. Fortunetly, a friend that lives nearby had the time to pick it up for me.
Some things puzzel me a bit. The paint scheme seems to be 3MA3, but the forks are not USD ?:-|
I´ll have to wait and see... Would prefer a 1 model engine form what I have read... wich wasn´t much yet, but some interesting posts on the 3MA section here. For the time being will keep on reading.
Juergen, jetting is easy ;D. Big pilots, very thick, long needle with sharp tapper, and huge main. Thats it... No, only joking,  maybe it won´t be that easy. I´ve noticed a lot of people struggle there. My task will be somehow easyer, because the bike doesn´t have a tittle and will only se action in closed circuit.
I always start by saying to myself I´ll keep things stock... haven´t succeded yet ;D. We´ll see.
Edd, the more I think about it, the more I agree with you ;D
Top engine builders seem to agree as well:
http://www.dea-engineering.com/?p=18
Been looking at your site Louis. It´s great. Your own dyno shead. How cool is that!
Followed with interess you testing with locked TPS. A shame you haven´t tryed the 0-1/8 curve with 3-4 degrees less advance.
Ybk, thanks. What used to be my 3XV I think it´s still under restoration by its new owner. The goal is to get it looking, as it did the day it left the assembly line.
Thanks for the re-welcome.
Hope I have some fresh pics soon.
Title: Re: 3MA trackbike project
Post by: Louis on May 06, 2014, 09:41:20 PM
Quote
Been looking at your site Louis. It´s great. Your own dyno shead. How cool is that!
Followed with interess you testing with locked TPS. A shame you haven´t tryed the 0-1/8 curve with 3-4 degrees less advance.

Thanks for looking at the site :), try to update it when I have something new.

I know exactly what you mean with the 1/8 curve with 3 till 4 degree less.

Its still on my to do list ;). (give me time, this year you know more)
Also the snorkel's (discussion) will be tested.
And the exhaust theory.

Working on many projects, info will come
Title: Re: 3MA trackbike project
Post by: casal-fan on May 21, 2014, 12:21:23 AM
Yesterday I welcomed the 3MA in my garage :)
Its looks OK, but in need of a lot of care
I took a quick look at it, confirmed it is a 1 model, cheked if engine was rotating freely, looked around again, cheked gearbox operating - very smooth.
Tryed to find the fuel open/close.  valve (only took 15 minutes ;D) opened fuel and straight away it started pooring out the airbox, a sure reassurence it is a genuine 3MA ;D Fantastic!!!
Front forks seals are leaking (would be changed anyway, of course).
The previous owner said that the bike has been regulary started, but has not been driven "for a while"... wich was a wise thing since the rear tyre is 14 years old...
So, I decided to start it. Choke, 3 kiks, and it started on both cylinders, without any suspicious sound - cool.
I took a final look, placed it at a corner in the garage, covered it... and it will stay there until winther.
Have a lot on my hands hobbywise, and it will no be possible to start working on it before.
I already started "sketching" a plan for it.
Enginewise, I´ll try to bring it a bit more alive then std. setup. There is a lot of  info on that in this forum already, so mostly I think I´ll use that information.
There is one mod. though I havent seen done yet, and I think I´ll try, wich is to shorten the pipe at the begining of the header wich I think maybe will give a bit more on the high revs, not drastic cut though because I don´t want to affect so much the effective operanting range of the powervalves...
Electronics will stay standart, I plan on doing some TPS testing (but Louis will probably (hopefully ;D) beat me to that). I hope it will be easyer then on the 3XV I had (wich responded in a negative manner to simple changes in airjets)
Chassiwise, still open. I have some other stuff wich would be nice to put on... but then it would kind of loose a bit of 3MA identity. Will have to tink about it. Geometri looks a bit luggish, dogbones and front lowering a must do.

So, sit tight...  I´ll try to document everything I do the best I can, with as much pics I can, and hopefully by next sommer I´ll have an interesting trackday 3MA (fingers crossed) ;)
By the way... how the heck do you remove the pillion seat ?:-| ?:-| ?:-|

Welcome to your new home little 3MA :)







Title: Re: 3MA trackbike project
Post by: Edd on May 23, 2014, 04:43:45 PM
LOL for the pinion seat took me a good few hours. Sometime the simplest things are the ones confusing us the most. Remove the seat then remove the small cover between the front and rear seats two screws then  bend over ansd look beneath the pinion seat two 6 mm bolts 10 socket and pull it free horizontally.

I must warn you at this point you will be unable to stop. Once the pinion seat is removed you are hooked and all other project will stop. So please think this through very carefully.

Edd
Title: Re: 3MA trackbike project
Post by: casal-fan on May 23, 2014, 08:05:41 PM

I must warn you at this point you will be unable to stop. Once the pinion seat is removed you are hooked and all other project will stop. So please think this through very carefully.

Ha ha... Thanks for the warning.
I kind of took preventive action for that not to happen, and the bike is burried in a corner, behind other bikes ;)
Thanks for the info!
Title: Re: 3MA trackbike project
Post by: Louis on May 24, 2014, 08:57:05 PM
Quote
Welcome to your new home little 3MA :)
She will be in good hands ;D

Quote
There is one mod. though I havent seen done yet, and I think I´ll try, wich is to shorten the pipe at the begining of the header wich I think maybe will give a bit more on the high revs, not drastic cut though because I don´t want to affect so much the effective operanting range of the powervalves...

Some info:
http://www.tzr3ma.com/exhaust-differences-3ma1---3ma3.html (http://www.tzr3ma.com/exhaust-differences-3ma1---3ma3.html)

If you don't want to give your 3MA a big tune.
Perhaps scoring a set off 3MA1 exhausts isn't a bad idea.
(They peek at 10.000rpm and can produce/handle 60HP)

Quote
Sorry just see it now, I have confused your bike with the one from jodydid.
It seems that your bike is a 3MA1, so you probably have the right pipes.
Also spotted some slicks on your bike, and a speed derestricktion unit (small red box)
There is a good change that your bike is already worked on


Quote
Electronics will stay standart, I plan on doing some TPS testing (but Louis will probably (hopefully ;D) beat me to that)
Still having some ideas for testing the TPS (using a stock CDI)
There could be a pony found, if we ratted the pickup by three degrees and use the 1/8 curve.
Hopefully ill know more this summer


Title: Re: 3MA trackbike project
Post by: casal-fan on May 25, 2014, 03:28:31 PM
Yes Louis, imo testing the curves in the stock CDI, together with making the engine more simple (fix airjet, etc) would probably improve the engine.
The question is the accuracy of the curves, because in the workshop handbook, yamaha does not mention wich engine speed (RPM) the curves are related to.
I tryed to look into the 3XV box curves, but kind of came to the conclusion that it would be gambling too much (2diferent solenoide air correction jets set - dedicated to each cylinder, etc).
With the 3MA, things look easyer, as well as it is documented that the air correction solenoides can be left out.

I confirmed that my bike is a 1-model, so the pipes are te ones with the header that has more area, thats good.
I think I´ll give it a go working with them, and at a later point perhaps ask Martin77 if he is willing or has the time to make me some.

We´ll see...
Title: Re: 3MA trackbike project
Post by: casal-fan on June 08, 2014, 02:32:18 PM
I got me some spare parts I needed from Japan, as well as an extra set of 00-barrels.
This also gave me the oportunity to look at the port layout.
A case of mass production. they need some clean up.
Port timings are ok for some considerable power. Measurements from top of the barrel gave me 196* on exhaust, and 127-129 on transfers. I don´t know how deck clearence is, wich means this numbers are quite irrelevant right now, just an indicator.
Looking forward to start working on this engine.

Title: Re: 3MA trackbike project
Post by: casal-fan on October 17, 2014, 09:14:49 PM
Time to start kicking some live in this thread.
Started dissasembly today... OMG, it´s even worst then the 3XV, wires and hoses all over ;D
Got the pipes, radiator, airbox out... and when I got to the carbs, and saw all the hoses... I went home ;D
Continuing dissasembly tomorrow, I´ll take some fotos.

Title: Re: 3MA trackbike project
Post by: casal-fan on October 18, 2014, 10:42:49 PM
So, here it goes.
Dissasembly started of course with the tank, and seat fairing. After that I came to the pipes.

Pic.1 I was interested in having a better look at the hole muffler mekanism... I did, and surprise surprise... a pseudo tuner just like me had been at work ;D Pipes still have the header ring fitted.

Pic.2 After that, the interest came to the airbox, maybe there had been some attempts at making the bike faster there...my guess was Wright, airfilter from kitchen exhaust apparatus. Pic2

Pic.3 Now, I could have a grasp at the powerplant... just.

Pic.4/5 Was of course interested in having a look at the plugs... they were lanmower plugs. After struggling ½ an hour to unplug the carbs I took them out, quick look, all seems OK. Just one airscrew is screwed, can´t get it out, because its all mushed.
Title: Re: 3MA trackbike project
Post by: casal-fan on October 18, 2014, 11:05:01 PM
Pic.1 Very important moment, tapping gearbox oil. It can say a lot of Things. Oil was clear, absolutly no shinny Things running around, very good.

Pic.2 Finally wrestled the engine out of the frame. Having had my "engine wrestling" kicks with 125ccs lately... this one is quite heavy.

Pic.3/4  Meaning was I should keep on with dissasembly of ancilleries as breaks and so on... but with the engine on the bench, I couldn´t resist taking some Measurements.
Started with squish. All this Measurements will help me with engine setup later on. Squish measured at 6 points, 4 in one cylinder and 2 on the other. Minor Measurement was 1.1mm, the largest number found was 1.2mm

Pic.5/6 Couldn´t stop investigating, head had to come of... it was tight. Pistons look good, very good, they seem to reinforce the info on the dash, Only 14000km. Deck clearence it´s not zero, a 0.2mm catches a bit... but it´s VERY close to zero.





Title: Re: 3MA trackbike project
Post by: casal-fan on October 18, 2014, 11:21:29 PM
Pic.1/2/3  Head back on, and it was time to get scrubbing... and it went on for a loooong time. The most boring in any rebuild, cleaning.
Result came nice though. Not as new, but a lot better then it was before.

Pic. 4  Plan for NeXT time is to go on with dissasembly, so I can get to the rolling chassi stage. Clean and rebuild what it needs to be rebuild such as brakes, suspension etc... by then I should have saved enough time ;D to get some new rubber, and then the process gets reversed - assembly.
Still don´t know how setup will be... cylinders, exhaust, all the Electronics... right now I´m thinking simplicity, this will be a track bike only. Has no tittle, and in my country Theres not a chance in a million years this could get plated.

Also looking forward for suspension rebuild and finding out what I´ll do with that. Forks with max. preload are showing 31mm rider sag already, and that was before breakfast... time will say
Title: Re: 3MA trackbike project
Post by: Louis on October 19, 2014, 11:46:50 AM
Quote
Started with squish. All this Measurements will help me with engine setup later on. Squish measured at 6 points, 4 in one cylinder and 2 on the other. Minor Measurement was 1.1mm, the largest number found was 1.2
Yes, most off them are just a touch above the 1mm :)

A the stock head volume is already close to a 11cc, if you want to skim the head to go closer on the squish you need to open the bowl as you go quick at ten or under it. So be careful if you are going that route.

Quote
Still don´t know how setup will be... cylinders, exhaust, all the Electronics... right now I´m thinking simplicity, this will be a track bike only
Yes, that is what I have learned within the years to :)
Keeping it as simple as possible, that is exactly what my track bike three is gona to be.

You are going great, think you will love her in the end ;D
Title: Re: 3MA trackbike project
Post by: casal-fan on October 19, 2014, 12:35:47 PM
Hi Louis thanks for the reply, and encoragement. Nice to know that people are looking over my shoulder and will probably say something if I do something drastically bad ;D

Louis, right now, when I think simple... I mean ALL Electronic aids off, and ALL fancy gismos off.
Fixed ignition curve, no VAJ, no TPS, no balance tubes. Just plain 2stroke engine... and take it from there. It would also be interesting to dokument how a 3MA runs like that. Haven´t found info on anyone that has tryed that.
But for this to be possible, you have to find out, what the RPM numbers on the igntion advance map are ;D

The head will be O-ringed. I measured the head gasket to be 0.3mm. O-ring conversion would bring squish down to 0.8-0.9mm
11cc gives a comp.ratio about 1:12.4
Without 0.74cc wich is the volume the gasket occupies, comp. ratio comes up to about 1:13.2 wich I belive still is a safe number for say 98 or aral 102.
Does 1:13.2 on a 3MA sound too high for youguys?
Title: Re: 3MA trackbike project
Post by: Louis on October 19, 2014, 01:19:56 PM
Quote
I mean ALL Electronic aids off, and ALL fancy gismos off. Fixed ignition curve, no VAJ, no TPS, no balance tubes. Just plain 2stroke engine... and take it from there.

That was completely my first intension with my trackbike three project to :)

Also found a ignition system that could do the trick.
http://www.ebay.co.uk/itm/yamaha-250-350-400-rd-lc-rdlc-tz-banshee-complete-new-ignition-racing-/181539245947?pt=UK_Motorcycle_Parts_13&hash=item2a44950f7b

Its a very clean ignition system (no magnet to see) no battery needed, just a push and off you go.
The 3MA1 flywheel does have the same tapper cone as a RD350, so this system should fit.

But i have delayed it because so much thinks need to be done for this project, and have so much thinks going on.
First now is to make it ready, those thinks can be ad later. ;)

Quote
Does 1:13.2 on a 3MA sound too high for youguys?
Don't think its to high, but the question could be. How much do you gain?

Higher compression, tighter squish will probably gain you some HP's but will it make the engine reliable?

I can imagine if you are racing on the last 0,1 seconds you can use all the hp's you can get.
But for enjoying your bike, reliability is something you need :o (certainly with a 3MA)

Think more Hp's can easily be gained by removing the airbox completely and go to fully open carbs.
(like the TZ250 3TC and 3LC)

This is something I will be testing next year on my road bike. (remove airbox, adjust jetting and see what it brinks)

Just a thought off me. You free to do what you want to do of course ;D
Title: Re: 3MA trackbike project
Post by: casal-fan on October 19, 2014, 04:43:43 PM
Louis, that ignition costs as much as the rebuild budget on this bike ;D
It would be nice to try, but I´m sticking with the stock ignition box... lots of Things to play with there ;D
Its just a shame that nobody found out the correct RPM for the ignition curves ;D

About reliability... well, if I manage to get the bike dialed up correctly, I do tops 8-10 trackdays a year and I have 2 more bikes to ride at the track.
A trackday has about 1½ hours of riding at about an average of 100km/k. Even if I use the bike for 5 trackdays, in one year (wich I wont), that would be 7½ hours on the bike a year, and only 730km. And thats a bright perspective because I usually crash or melt the engine long before that... or crash because I melt the engine ;D Riding fast is still an ungoing project for me...
But, it´s just to say that with these timeframe numbers, if the engine is setup correctly even for a bit more harder specs, it will still have A LOT of time between rebuilds. A road bike is of course VERY different.

I would love to try settings without airbox... problem is noise. In Scandinavia pretty much max. 95dB is std. for the tracks... and the 3MA is not the best exemple of a quiet bike ;D

Look forward to see the ideas on your trackbike3... I personally am very excited about working on my bike.
It´s all good, as long as someone trys different Things, bad or good, everybody learns and there is a contribution to keeping the 2strokes going!
Title: Re: 3MA trackbike project
Post by: casal-fan on October 21, 2014, 12:27:37 AM
Interesting picture.
Added a few more curves for comparison.
250GP curve is "pushed back" 2000RPM, so peak power would be at 11000RPM
Wonder how 0-1/8 curve would work with a pipe toping at 11000rpm or even just a tad over...
Title: Re: 3MA trackbike project
Post by: Louis on October 21, 2014, 09:51:19 PM
The 0-1/8 is certainly not bad for a 89 ignition curve, it has potential. ;)

Making a pipes for the 10.750 a 11.000 RPM range is on my to do list. Just for testing that theory
Title: Re: 3MA trackbike project
Post by: Edd on October 22, 2014, 10:35:13 AM
Hi

Read the last few posts so I might have miss some of the detail. Cant help to think you are going down my street and I have a lot of issues to sort and to deal with but I am getting there ;D. I run a compresion of around 1:11 with new squish I have a compression of around 1:12. (These are guestimates) havent calculated the numbers my squish measured was 0.76mm and with head gasket back in 0.89mm now. I think I am with Louis on a squish of about 0.9 to 0.95 but school is not out on this verdict. I am still experimenting on this ;).

Will love to see your results. I run the tz 250 curve but have moved it down by two degrees across the rev range. I still have carb issues to sort in my view.

Eddie
Title: Re: 3MA trackbike project
Post by: casal-fan on October 22, 2014, 10:57:45 PM
Jes, Edd... going pretty much down your road, I know. Not a case of "copycatting" though. I just think that we both are planning to use our bikes in a similar maner, so it´s not that odd that the final setup will be similar.
I have no previous experience with the 3MA... I only know what it has been written here.
Since there seens to be so many hick-ups on setup with all the management aids in this engine, I am inclined to remove them all, treat it as a plain simple 2stroke, and take it from there... if it doesn´t work, well... then it doesn´t work ;D
As I wrote before, this bike will not be used for road riding, track riding is different, it´s just open or closed throttle with a bit maintainence throttle here and there ;D.
Thanks for the squish info, appreciate it.

Louis, I just found a post by you, where you writte about the 0 curve in association with a higher RPM pipe. I also belive this would be interesting to experiment, specialy with the chance of retarding the curve 2-3 degrees by use the "pickup move" you invented.
I tryed to measure the 00 pipe today. It is quite hard because of the curvy and box shape. I measured diameters in intervals of 10cm with a line, and converted the "straight line" measurement to perimeter measurements. Not very accurate I´m sure, but the results are not what I expected.........

More to come soon...
Title: Re: 3MA trackbike project
Post by: Edd on October 23, 2014, 07:23:13 AM
Like to see what the standard cdi will do with those mods, I have a zeel fitted and that is also maybe another tumbling block. Remember dont remove the neutral switch and wire when you do your mods with the standard cdi if neutral wire is not connected no spark with std cdi.

Edd
Title: Re: 3MA trackbike project
Post by: casal-fan on October 23, 2014, 10:40:27 PM
Found some time to put the pipe measurements I took together, and have a good look.
Have to emphasize that these measurements are simply the ones I was able to take, to the best of my ability.
By no means I am 100% sure these are the real dimensions of the pipe.
The header for instance... it is very hard to fing the precise spot where the tapper begings to deepen, and I just used my best judgement and so on...
Still, I am confident the dimensions are not tottaly off, and can give a good pointer.

Lenghts: cylinder-60mm / header-330mm / divergent cone-300mm / belly-100mm / convergent cone-220mm(???)

But, the real surprise was that these dimensions are close, to what the latest pipe building softwares spit out when asked to design a good pipe that tops at 10000rpm, combined with 195* exhaust duration...
Just looking at them... would never have guessed.

Next step, try to find out how to best modify these pipes, so they can can mimic a good design for a bit more top power RPM, and just a tad higher exhaust timing.
If some of youguys has measured the 00 pipes and has some comments on the measurements I took, I´d appreciate it.
Title: Re: 3MA trackbike project
Post by: Louis on October 25, 2014, 09:00:10 AM
Not bad designed for a 89 bike isn't it :)

It is certainly difficult to measure the diameters as the material is thick and probably the pipe has some internal plate work to inside.
The manual says this 34 - 108 - 23
(http://i1186.photobucket.com/albums/z376/tzr250-3ma/3MA%20japanese/3ma1exhuats_zps66c13ad3.jpg)

A stock pipe doesn't perform badly, in fact I think it will be difficult to outperform it by making a new pipe designed to peek at 10.000rpm





Title: Re: 3MA trackbike project
Post by: casal-fan on October 25, 2014, 12:25:58 PM
Hi Louis.
Jes, it is very difficult... to make Things worst... I did not have much time to do it.
I had seen the pic you post before, also tryed to look at the files on redandblue´s pure2strokespirit site, but can not manage to open them, tryed to setup my computer in different ways to open the files without luck...

The Measurements I took are with steal wire (cable wire) around the pipe, converted to diameters from that. I also substracted 6mm to each diameter mesurement to compensate for material thickness and wire section.
Louis, one Measurement wich is really hard to "guesstimate" is the lenght  of the last cone (after the belly).
You have exposed the last bit of that cone when you changed to tyga silencers. Did you take a "guesstimated" ;D Measurement then?
My 210mm lenght, Associated with 116/23 (start/finish) diameters give a closing angle of 25*. That is a bit Sharp... maybe the last cone is in reality a bit longer??? ?:-|
Title: Re: 3MA trackbike project
Post by: casal-fan on October 26, 2014, 10:25:59 PM
I took a quick drive to the workshop yesterday to give the pipes a "better" look.
I also realised that the methode I used to measure diameters was incorrect.
This time I took reference in the belly measurement from the manual (108mm) and the perimeter I mesasured at the belly as well. With those two measurements I calculated a percentual correction factor and used that to convert all perimeter measurements to diameters.
Another thing I wanted to do was to find the precise spot where header stops and diffuser begins.
At 270mm, the angle changes. Contrary to what it can appear, at least in the measurements I was able to take, the diffuser is a constant angle, not 2stage.

Won´t use more time with the pipe. I guess, the measurements are quite precise now, apart from the convergent cone wich is still a bit of a question mark. 220mm seems to be OK after looking at all the pics I found of a cutted/stripped pipe.
I also gave my best shot at modifying the pipe the best I could, so the cutting would be as simple as possible.
After a couple of hours yesterday, analysing some different things, I came to the modifyed pipe below as the best compromise.
I hope this pipe, combined with a tad higher exh. port (197*) and a tad more agressive ignition will top at 10500-10750 RPM.
Theori done, now the projects moves forward...
Title: Re: 3MA trackbike project
Post by: Louis on October 26, 2014, 11:11:04 PM
Quote
Louis, one Measurement wich is really hard to "guesstimate" is the lenght  of the last cone (after the belly).
You have exposed the last bit of that cone when you changed to tyga silencers. Did you take a "guesstimated" ;D Measurement then?

Sorry I have forgot to measure it for you today, I'll try to do it tomorrow after work :)

My ten point on the exhaust thing

From Paul his bike, seems like the 105 mod is peeking at 10500rpm
(http://pure2strokespirit.net/phpbbforum/i172.photobucket.com/albums/w26/ndwedwe/IMG_2551Medium.jpg)

The 105 mod seems to cut away a total off 27,5mm
(http://i1186.photobucket.com/albums/z376/tzr250-3ma/105mod_zpsa1d86255.jpg)

Your Casal mod 8) takes away 40mm
(http://i1186.photobucket.com/albums/z376/tzr250-3ma/casalmod_zpse657f3cb.jpg)

I'm guessing it will peek between 10750 till 11000 ;) :D

Cheers


Title: Re: 3MA trackbike project
Post by: casal-fan on October 26, 2014, 11:49:29 PM

I'm guessing it will peek between 10750 till 11000 ;) :D

Noooo... you mean something like this??? Don´t want that... very expensive ;D
http://www.youtube.com/watch?v=ZHomWqE4F6s&index=9&list=UUEnyKyVPKI2lANNyIVpNuqA

I think this was Pauls ignition setup... I was looking into using just a tad more at max. power... thus the shorter pipe, maybe, perhaps... who knows, peaking at about the same RPM...
And... this lenght gives decent % numbers without much work... well see...

Louis, it would be great if you could measure the convergent cone. No hurrys though...
Title: Re: 3MA trackbike project
Post by: casal-fan on November 11, 2014, 10:09:13 PM
I´ve finished the barrels today.
Had thought about sending them to Martin, but since the timings are so good to start with I thought of doing it myself.
Nothing serious.
All the ports got a clean up, there was a very prononces lip on the edge of all the ports, worst case was 0,5mm. Some casting line cleaned as well.
Main job was the aux. exh. ports that were open towards the main exh. to a distance of 5mm. The goad, to gain a bit more blodown area, to sustain a little higher top power rpm regime.
Also moded the cylinder "skirt" at the intake side, after seeing it done on Louis site... it gives meaning.
After that measured port timings:
Exh - 197* ~ 198*
Sub-exh - 191*
A - Tran. 125* ~ 126*, climing up to 128*
B/C . Tran. 128*, C just a tad lower.
I wasn´t looking for dead accuracy on the timing measurements since I was not changing them anyway. Belive the timing is good for what I´m trying to achive.

Took some pics.
(Before you guys go picking my head about the honing, keep in mind pics were taken with flash. It looks terrible but it isn´t ;D
Just 10-12 rounds at very low speed)

Title: Re: 3MA trackbike project
Post by: Louis on November 11, 2014, 11:01:05 PM
Looking good :)

Quote
Before you guys go picking my head about the honing
I don't see any problem with it, it holds the oil better. 8)


You may want to investigate, the opening space from the booster port.
The reedblock is blocking it quit heavily, perhaps a spacer could clear it up
See for your self.

Nice shorting those legs :D

ps. Have forgotten to measure the pipes :-[, will try to do it in the weekend
Title: Re: 3MA trackbike project
Post by: maccas on November 11, 2014, 11:57:19 PM
Great work Rui! Really interesting stuff regarding the pipes!

Dan
Title: Re: 3MA trackbike project
Post by: casal-fan on November 12, 2014, 07:50:25 PM
Dan, good to see you still tune in here once a while.
Having decided to use the std. pipe, I really would like to have it analysed the best I can... and perhaps go for something wich is a bit different then what other have tryed if possible. Even if the result is poor... at least it got tryed...
Hope you continue development of your 3XV soon again... always interesting to read about what you´r up to.

Luis, I would be very gratful if you could measure the last cone in a 3MA 00 pipe, that would give me a really good picture about the std. pipe
About the reeds... Yes I´ve seen it, and I´m thinking spacers yes.

Title: Re: 3MA trackbike project
Post by: Louis on November 14, 2014, 10:45:52 PM
Hello Rui,

Have measured the end can, but have to say its a bid tricky as it is twisted and has a strange bend in the end.
(http://i1186.photobucket.com/albums/z376/tzr250-3ma/TZR250%20FORUM/eindcone_zpsff037666.jpg)

I came at 215mm :)


Title: Re: 3MA trackbike project
Post by: casal-fan on November 15, 2014, 10:11:37 PM
Hi Louis.
Thank you for having measuring the cone. Yes, it is very hard to measure.
About the exhaust, maybe I´ll change to aftermarket silencers. Maybe it is easyer just to do that then working with the std. ones.

And... a bit more regard the rebuild of the little 3MA.
I wanted to do a bit more research that could reveal a bit more about the engine, and it´s condition.
A big question mark is the question if I would be doing more bad then good, by starting replacing parts by new...
F.exe. I´ve once changed crankseals on a bike, just because "it would probably be wise", not because there were any sign that they were bad. Result, the one ones (from yamaha, in a yamaha marked plasticbag) one was leaking within a months use...
I started the bike when it was still all together, idled OK, not too much smoke, etc.

I decided then to get the engine measured through, and then decide if I would go for a full rebuild, or if that simply was not necessary.
First of all, calibration of the instruments. When measuring 100s of a milimeter, calibration is paramount.
The micrometer was calibrated.
The bore gauge was also calibrated, using the calibrated micrometer.
That done. I started measuring the cylinders. This is very hard to measure at the places that the manual says... actually impossible. No good measurements can be taken from the top of the exhaust port, to the bottom of the transfers boost port.
Both cylinders measured, I started measuring the pistons... again, the manuals (or as I undestand it, not because I can read japanese... just by looking at the number  :)) 5mm from the piston skirt. Impossible on this piston because the cutout at the intake side goes higher then 5mm, so I measured at the point where the cut out stops.
Ring gap was off course also measured.
Also performed the "searchblade" test (inserted between piston and cylinder)
Next, measured the crank. It was very, very acceptable, everything!
Then, I opened the clutch side cover, to measure the clutch. Again, very good results.

Here are the cylinder/piston measurements I took:

                                       Measured                     Manual
Right cylinder                 56,05-56,06               56,00-56,02
Left   cylinder                56,045-56,06             
Right piston                    55,98-55,99              55,95-55,98
Left piston                    55,985-55,99   
Blade test                            0,5         

Ring gap right               
3mm from top                      0,45                     
10mm from top                    0,4
Ring gap left
3mm from top                      0,5
10mm from top                    0,45

After having taken the measurements, and referencing them to what the manual prescribes... I started scratching my head ?:-|
Cylinders are marked C... and pistons are marked M
Both cylinders and pistons have greater measures then manual prescribes...
Then I looked, pistons are marked 2XT00, and cylinders 3MA00. From what I read here... it does not add up. I´ve read 2XT00 pistons are for the SP??? and have a lower (flater) dome at the top?
I was curious... so out I went to buy some chewing gum :D
Chewing gum placed 4 places in the combustion chambers squish, and pressed with the piston, to see if the squishband area was of consistent thickness. It was, so in my bike anyway 3MA00 cyls and 3MA00 head goes good with 2XT00 pistons.
This also meant that I could not use the measurements from the 3MA00 manual as reference.
I ended up with the folowing results for bore/piston clearence.
Both left and Right side - Max. clearence 0,07mm   Min. clearence 0,06mm
Maybe this would not be acceptable for a 56mm piston, BUT when taken into consideration that measurement of the piston should have been taken at a place 5mm lower, I think these results are very good.
Both pistons and rings will be used again.

On to the measurements I took on the crank. Again, very good. See picture below.

And last, but not least, I measured the clutch.
Well within specifications.

1st friction plate - 3,6mm - manual says (or at least what I can interprete) 3,4-3,6
Rest                   - 3-3,05mm  manual 2,9-3,1
Springs              - 39,7-39,9   manual 38,1-40,1

So... IMO, very good results all the way. This engine has very little fatige, wich corrobarates the kms shown on the tacho.
I will put the engine together again, with new gaskets, but will not change parts. That would be in my opinion a waiste of both money and good OEM parts. And I would be trading OEM parts in good condition for non OEM aftermarket parts.
I gave the parts I had out, a good clean up, pistons, clutch plates, oilpump net, etc etc, and when the new gasket set comes, I´ll close the engine again.
An interesting thing I noticed. The oilpump gear is the one that spins the gear for the gearbox oil pump. Do you guys have a trick to how to run the gearbox oil pump while removing the 2stroke oil pump?

And, last but not least, "if you don´t have pictures, it never happened." Isn´t that what they say?
Unfortunatly my phones bat when out and I didn´t take as many as I would like to have done.
Title: Re: 3MA trackbike project
Post by: casal-fan on December 28, 2014, 03:35:03 AM
Had a couple of hours today to drive to the garage.
I´ve had the pipes soaking with caustic soda for about 1½ weeks ;D so I thought it was time to empty them... either the "potion" was too weak or the pipes were clean to start with, almost nothing came out.
After looking at the silencers, I decided to cut them out and replace them with some aftermarket ones. They were damaged, and it would be harder to fix them then just replacing them.
This also gave me the chance to take a closer look at the end cone, and just as Louis concluded, it is also my best judgment that the lenght is 215mm, not 220mm as I had estimated before.
With this new knowledge, the pipe-cutting plan was revised.
Still keeping the 910mm total length. A bit too short for my target of 10500(ish) max power rpm, some might say, but I´m gonna stick with it because I would really like to try the 0-1/8 curve. More advance-less heat in the pipe=shorter pipe for the same target rpm. Will see how it goes... interesting trying different things.

For the pipe freaks, here is some more data on the pipes, after they are modified. All measurements to the best of amator judgement, nothing written in stone.
Piston to pipe flange - 60mm - 55cm3
Header - 240mm - wall angle 3,58* - 360cm3
Divergent cone - 300mm - 10,8* - 1552cm3
Center - 95mm - 870cm3
Convergent cone - 215mm - 22,5* - 826cm3
Pipe/cylinder volume rate ~ 27
Title: Re: 3MA trackbike project
Post by: Louis on December 28, 2014, 11:46:19 AM
Quote
Still keeping the 910mm total length. A bit too short for my target of 10500(ish) max power rpm, some might say, but I´m gonna stick with it because I would really like to try the 0-1/8 curve.
I'll will be following you on this, only will shorten the stock pipes to 915 a 920  to get a (Hopefully) peek at around 10.500 a 10.750rpm
Will see it on the dyno if it is spot on, or need to be shortened a tach more :)

Also working to readout the 3MA-CDI (oem curve) to see if it is exactly as we known.

But it is getting colder, so it will take a bid more time to do it
Title: Re: 3MA trackbike project
Post by: Warwick on December 28, 2014, 12:12:22 PM
Rui, Just to confirm: oe 3MA pistons are marked 2XT inside, so yours are the correct fitment and nothing to worry about :).
Title: Re: 3MA trackbike project
Post by: casal-fan on December 28, 2014, 10:56:35 PM
Hi Louis.
We´ll see... I would like to try the 910mm pipe very much, together with 0 curve. Maybe it would not work, maybe it would???
To my knowledge it has not been tryed. Your testing of the 0 curve with the standart lenght shows IMO signs of wanting a pipe that does not top so soon, again just my opinion.
A small problem, I realised yesterday is that by cutting 35mm, the last cone of the pipe will probably not clear the subframe :-[ :-[ :-[, and more work will be involved... or maybe set the length to 915mm, that would clear the subframe, and make the pipe modification work real easy, only 30mm cut out at the very start of the pipe. Those 5mm would save a lot of work and probably would not make any noticable difference performancewise... we´ll see how it goes...

Warwick, thanks man... that one was picking my brain.
Title: Re: 3MA trackbike project
Post by: casal-fan on January 04, 2015, 02:24:58 AM
Little by little, the project moves forward.
Today, rebuilding the front brake system. Everything was very dirty. After a thorough clean up, parts like seals, master cylinder, pistons, etc were in good condition, and I reused them again. Like I said before... no point on replacing perfectly good parts.
A good clean up, seals were lubed, pistons were polished, and topped everything with a set of very cool braided brake lines red/blue anodized, wich are known to improve top speed by at least 10% ;D
Some pics of todays work.
Title: Re: 3MA trackbike project
Post by: Neal on January 04, 2015, 06:26:30 AM
What brake fluid are you going to use ? I had brake fade with Bellray so be carefull
Title: Re: 3MA trackbike project
Post by: casal-fan on January 05, 2015, 12:09:29 AM
Hi Neal.
No special preference on brake fluid. I tend to use statoil because I get theyr products very cheap. As long as it is a known brand, and DOT 4.0, I use it.

Was at the workshop again today.
Finished renewal of the rear brake system. This one was not as easy as the front. The system had barely any fluid in it, so I had to use compressed air to get the pistons out. It took 13bar to push them out. I did what I could to get it all in good working order again. It is a boring job, but it has to be done. Brakes are a vital component.

Then I started dissasembly of a GSXR600 K5 rear shock.
I bought it to replace the std. 3MA unit wich by now is 27 years old. Spring rate is acording to some suspension websites 7.5-8 N.m
I´ll have to see how it works out.
The shock was in very decent condition, with no signs of leaks or major ware.
Procedure was.
Empty the blatter, take it out. Take compression adjuster out and empty the oil.
Turn on the spring tension adjuster on full, secure the spring, back out the tensioner, and then you have enough space to thake the snap ring that secures the spring out. Then the spring comes out.
I could sware I had some 5 weight suspension fluid at the workshop, but couldn´t find it... so, assembly had to wait.
Took some pictures... everybody likes pictures ;D
Title: Re: 3MA trackbike project
Post by: casal-fan on February 18, 2015, 06:42:54 PM
Engine is closed Again, after having inspected it.
Dissasembled and cleaned the gearbox oil pump (nothing to clean really), ditched the mixture pump and made a cover, cleaned clutch components and soaked friction plates in new oil after having been cleaned, also put some texture on the metal plates. PVs cleaned, filed a bit to be 100% in phase with the ports, reassemble with new seal kit.
Squish came out at +- 0.85mm with 0.7 basegasket and O-ringed head ... bit tight maybe???

Also started overhauling the carbs.
The needles man... how the heack do you inspect the needles??? Have to figure that one out later...
One carb was a pain, colossal. Had to drill a pilot jet and an airscrue out. At a point I was about to give up, but managed to get everything out, and after a good clean with solvent and some punishedment with 12BAR compressed air, there was passage through all the holes.

Next step, chassi Work.

Title: Re: 3MA trackbike project
Post by: casal-fan on February 21, 2015, 11:34:42 PM
Another day, another step.
Started by doing a simple thing, removing the speedo restriction and cleaning the instruments.
This Means that I am selling a POSH FIRM speedo derestrictor.
I thought of using it, but selling it would bring some much needed funds to the rebuild :D
Looked if it was the same as the 3XV one, but apparently it isn´t.
I also have an M-MAX derestrictor for the 3XV I´m putting in the too sell section.
The instruments came out nice.

Next, I stripped the chassi and cleaned it.
This also gave me the oportunity to start cleaning the small chassi parts and began putting them on.
Tryed the GSXR shock... the bastard doesn´t clear the swingarm, spring has to have a bit more clearence at the top, will have to tjek that.
With so many bits out, I can now focus on doing them, wheal bearings, steering collumn bearings, sprockets, etc etc... still a long way...
Title: Re: 3MA trackbike project
Post by: Paul on February 22, 2015, 11:57:52 AM
very smart work going on there
which country are you in?
Title: Re: 3MA trackbike project
Post by: casal-fan on February 22, 2015, 01:28:27 PM
Hej There Paul.
Thanks for the comment.

This bike has been standing for sooooo long, that a complete strip down was unevitable.
Takes time and money... but in the end I hope it will be worth it.

I´m in Denmark.
Title: Re: 3MA trackbike project
Post by: Louis on February 22, 2015, 02:51:29 PM
Quote
Takes time and money... but in the end I hope it will be worth it.

Of course it will be ''worth it'' ;)
Also construction and bring your own ideas into you track bike is part off the hobby and nice to do :)

As you have the engine almost ready, Frame uses the big parts.
One's you have the shock mounted and frond fork fitted (with wheels) after that it is going fast

Title: Re: 3MA trackbike project
Post by: Paul on February 22, 2015, 03:01:28 PM
I´m in Denmark.

that's right, i forgot
my 3MA is coming from SA to UK where i am now based, i am excited beyond belief, i can finish it properly now on a decent dyno, it is a rocket ship!!!!!!
Title: Re: 3MA trackbike project
Post by: casal-fan on February 22, 2015, 09:34:03 PM

Of course it will be ''worth it'' ;)
Also construction and bring your own ideas into you track bike is part off the hobby and nice to do :)

Louis, what worries me a Little bit it´s exactly the part you writte about bringing new ideas... it will have a few, specially enginewise, and engine management wise, that I haven´t read about, so probably haven´t been tested yet.
But... more on that later.

By the way Louis, I forgot to check the resistence values on the TPS resistor in the several throttle opening positions... and now TPS is out. Do you have them???

Paul.
Another 2stroke in the old continent is always a good thing, maybe Winther will be milder NeXT year. ;D
Title: Re: 3MA trackbike project
Post by: casal-fan on March 05, 2015, 10:00:03 PM
Little change of plans...
Have some RGV parts wich won´t be used this season.
Instead og using a lot of Money and time refurbishing 3MA parts, I decided to use the RGV parts.
I wouldn´t do it if it was a road bike, but for the track... I think (hope :))it will Work OK.

Complete front end will be VJ22, (if I have time to spare maybe install andreani suspension kit)
This front end was completly rebuild for 2 years ago, and was running on another of my bikes.

Rear Wheel - RGV. Made the Measurements already, It can be done just by making new spacers, using RGV hub and sprocket, as well as brake disc.
As a plus, I´ll be saving some Money in new rubber (at least for now), I recon there are around 6 trackdays on the supercorsas I used last year. Another plus is that I have a spare rim set with wets mounted.

If it Works out good, I´ll make a drawing of the spacers in case others would like to do this conversion.

Measuring... Again, and Again... to Work out how the spacers should be done.
Title: Re: 3MA trackbike project
Post by: Louis on March 08, 2015, 09:28:13 PM
How do they say it in English.

''There are more roads leading to ROME'' :)

You see the RGV frond and end a lot on race bikes, so way wont it fit a 3MA


Like this to 8)
(http://i1186.photobucket.com/albums/z376/tzr250-3ma/w1thzp_zpsmm1lcirh.jpg)

Title: Re: 3MA trackbike project
Post by: casal-fan on March 08, 2015, 09:54:56 PM
Hi Louis.

Well, I had the stuff laying around from another bike wich is going to be completly restored.
My 3ma front Wheel had almost 2,6mm run out at a spot, the forks would have to be completly redone with bushes, etc etc... and then a set of tyres as well. It was the more economic scenario for me to use the RGV stuff (hope the purists don´t get offended ;D

I spent some more hours at the workshop today.
Since I have to wait for new headcolumn bearings, I inspected and cleaned the loom, bolted the engine on, and started modifying the reed Cages. The middle divisor out, and 3XV reed stop on the upper side for better clearence to the boost intake port.
Also took a closer look at how close the reeds are to the crankshaft.
The incomming mixture just hits a wall (the crank) straight away... maybe some reed spacers would help...

Title: Re: 3MA trackbike project
Post by: casal-fan on March 14, 2015, 12:32:08 PM
Yesterday, I cutted the pipes... no way back now :-\
If it Works, it Works, if it doesn´t... I´m screwed ;D, this is the only track bike I´m focusing on for this sommer.

Title: Re: 3MA trackbike project
Post by: casal-fan on April 02, 2015, 02:58:32 PM
Been going at it yesterday.
Worked on the intake system. Trying to play smart**s, I decided to do some profound modifications in the intake system, as this area seems to me is not exactly the best designed area of the 3ma.
The reed Cages saw the middle separator dissapear :), cutted some Carbon reeds, 0.3mm with no cut in the middle to add some stiffness. The top reed has a litttle spacer between the reed and the stopper (an "invention" by Tony Doukas from the USA, that uses this trick on banshee and RD/RZ reeds, I have tryed it, Works good), Then the upper stopper was opened to 12mm (bottom 10mm). All this in a nutshel, just to try and promote flow through the upper reed. Works or not??? Time will say...
I also got hold of a pair of 10mm spacers, to go between the reed Cage and the engine block, so that the incoming mixture doesn´t directly colide with the crank, but has a bit more area there, hopefully helping directing the mixture to where it should go.
The carbs got the final inspection. O-rings in the needle valve seat were changed (they were rotten :))and the initial jetting setup set in #20 pilot - 1st clip from top - #380 (main jet size doesnt matter really, it will have to be tuned.)-This for 30:1 oil mixture.
The fixed airjet setup was also done, with spark plug "cap" - thanks Louis :)-Works a treat.
Also started to install the USD front end.

Hopefully I´ll have another go at the bike today.

Title: Re: 3MA trackbike project
Post by: jools on April 02, 2015, 10:50:28 PM
Love your work mate.  ;)

Nice tips on the reed valve spacers too.
Title: Re: 3MA trackbike project
Post by: casal-fan on April 27, 2015, 11:32:40 PM
Been busy ;D
Cleaning parts, welding pipes, rebuilding and repacking some old silencers and fir them to the pipes, modifying a sub frame I had laying around so I still have a 3MA original one, bushings for the rear whell, setting TPS voltage to 0-1/8 curve, modifyed pick-up holes for less 2-3 degrees advance, sprockets, chain - messed up big time there, the sizes I choose it´s not gonna work because of the little longer shock I fitted.
Sorting wiring, mounting EGT ( only one... couldn´t fing my doble EGT monitor >:(), sorting out the rear caliper to work without the torq arm (need4speed solution, thanks ;D)
And even got to take a shacky pic, before phone shut down with no power :(
I`ll try to take pics of everything tomorrow.


Title: Re: 3MA trackbike project
Post by: casal-fan on April 28, 2015, 08:00:12 PM
IT LIVES ;D
IT`S ALIVE ;D

Started this afternoon by taking some pics, as promissed.
Made a setup for a tiny, light weigt LiPoFe4 bat. wich I just spent fast to the instruments frame, finished up connecting EGT, coolant, oil, made some premix...
Let the fuel flow, with opened "empty carbs crues" and a hose connected to look at the fuel level... 5mm on both carbs without a single leak... the prep work on the carbs payed of, cool.
Coudn´t resist to fire it up ;D
Initial setup with fixed  0-1/8 curve, modified pickup for minus 2-3 degrees, 35mm shorter pipes, fixed airjets, #20 pilots, all down needle, #380 mains, #60 air jets
carbon reeds, mod. cages, 10mm reed spacers, blocked interconnecting manifold pipe, eliminated chek valve connection, 10 iridium with reed ngk caps, 0.8mm squish, cleaned up 00-cyls. snorkel ring removed and automotive ventilation filter as airfilter ;D
Started at 4th kick with shocker... and sounds OK for an initial setup. Mains are waaaaaayyy too big, the bike can not take a hand full throttle, without 4stroking a lot, but the mid throttle opening i very crisp ;D
Won´t have time to continue the next few week, but I look forward for the 1st test ride.

And, as promissed, pics.
I don´t think they show it that good, but in relation to the state the bike was in when I bought... what a transformation...
Title: Re: 3MA trackbike project
Post by: Paul on April 28, 2015, 08:57:23 PM
Nearly there.
Title: Re: 3MA trackbike project
Post by: casal-fan on April 30, 2015, 04:44:36 PM
After a hole morning palying with carbs, I now feel like a true 3MA owner ;D
Float height keeps playing my patience, and it seems that it plays a MAJOR role on how the engine behaves.


Title: Re: 3MA trackbike project
Post by: casal-fan on April 30, 2015, 08:44:18 PM
A "little" something I noticed on my engine.
Right side cyl. is smoking a lot more then left.
The left pipe is also getting much hotter, and still its carb was at at least 3mm more float height then the right hand side.
Investigating a little: is this optical ilusion, or does this bike also seem to smoke a lot more from the right side???
Take a good look from 0.29 to 35 seconds.
https://www.youtube.com/watch?v=DXyknHVh2FY

This is exactly what´s happening with my 3MA. Is this normal??? White smoke, good smoke, it´s not black smoke of the bad kind.
Hopefully this enigma will also wake Luis up from his hibernation ;D

Left the workshop with #280 mains, #130 air, and still not reving clear (not riding, just blipping the throttle). This with snorkels mounted but cutted at the rings.
Have to find out what´s causing overheating of cyl. nr.1, and then another experiment. 3XV boost bottles.
One explanation of the midrev overrich could be an overstrong pulse signal at the carb wich maybe can be smoothen with boost bottles. 3XV seem rather small, but again the intraweb provides, with lots of interesting tips ;D (see pic.)

Another very important question.
Ignition coil, orange and black wire. Which on the top and wich on the bottom???


Title: Re: 3MA trackbike project
Post by: Paul on May 01, 2015, 06:15:23 AM
Shame man. It can be frustrating.
What do your plugs look like. Float level shouldn't mess you around that much. Set it to the manual and turn your back on that one. Go through that carb again, swap parts with the RHS one.
Coil wires... Doesn't matter which way around.
Title: Re: 3MA trackbike project
Post by: Edd on May 01, 2015, 07:15:24 AM
Hi Rui

Dont want to disagree with Paul ;) the coil will work both ways around but if you have a careful look at the coil it has a positive and negative on it, with orange on top if memory serves me right. The jetting will give you a hard time; the floats will settle eventually as they are in the fuel. What I realised is if they mug around drain the bowl at the bottom screw if you know what I mean with tap on prime. So it fills as it drains then close after 10 seconds and check level again repeat procedure if it doesnt settle after a few goes go back to float setting. I am running 220 mains with 120 fixed air jet with open bottom half of airbox only same squish but avgas. I think your idea with the boost bottle is brilliant and worth a go. On my RZ 50 they connected it with a hose it was a distance away from the intake rubber. So you can move them around if required.

First go for a short ride to clear the cases then see what the pipes are doing. Are you on a pump it might be oiling more change connections around and see. Have you interconnected your intake rubbers?

Edd
Title: Re: 3MA trackbike project
Post by: Paul on May 01, 2015, 08:48:05 AM
If you swap the spark plug caps from left to right you'll see bike runs the same. What is known as wasted spark. They both fire every 180deg.
Title: Re: 3MA trackbike project
Post by: casal-fan on May 01, 2015, 11:48:44 AM
Thanks for the input guys.
Paul I don´t mean HT coils to the plugs, I ment wires Black and orange, that feed 12V to the coil ;D
Listennig Paul, I´ll take your answer as reference, next time at the workshop.

Hi Edd.
Got you mate, haven´t spotted + and minus on the coil. As usual I  planned on taking pics when dissasembling, and as usual I end up never doing it ;D
Ride, not possible at the time, as the gearing I´m running, or planned on running 13-43, the chain won´t clear the swingarm pivot. I´m waiting for 14/45.
About the boost bootles, ja, I always ment trying them just to see how it goes. At the time, I have no intake interconnection between cylinders, That is plugged.
In theori, there are some "pointers" that could point to boost bottles as a good thing on 3MA. While the carbs are rather large (compared to 28mm on the 3XV f. exe.) the length between reeds and carb is very short. Looking at reed valvers like the OW59, the intake manifold is quite large/long, and they run 38mm. Maybe, on the 3MA some more area created by the boost bottle would prevent the massive blowback that I clearly can see at my airbox now... it´s all wet...
Thanks on your opinion with float levels, appreciate that. I´ll try and set them up at 5mm. At 10mm, fuel runs into the air compensation system.


And to continue the saga on too many ideas, and not the time or the adequated faciliies to try things out, last night while looking at options, after realyzing that the overrichness at middle RPM is a fact that not easily can be overcome, I found out something else that could be of interess to experiment.
Trackbike - simplicity - but it seems that with the fixed air jets, there is always an ongoing battle between a main jet that is the smallest possible, so that there are no dead areas in the rpm range, but still large enough not to seize the engine.
To add to simplicity, I decided on a fixed ignition curve as well. The most adequated one (actually quite similar to What Paul posted was the best for his 4XV beast) seems to be the 0-1/8, with a bit pickup input to bring it down.
But according to Louis last research on ignition curves, the 0 throttle and full throttle curves are quite similar, and can be made to almost match by adjusting the pickup for more or less advance.
Then, some research on how the VAJ works shows that the full throttle curve operates one solenoide to be opened form 4-8000 rpm - about the area where air correction seems to be a must on these engines.
So, in theori using full throttle curve with maybe a bit more advance, blocking the solenoid that doesn´t matter with an M4 bolt, and working with the other solenoid (and even the always open) would give full control over aircorrection, while still having only one ignition curve and TPS disabled.
Just a thought, it would be interesting to try.

Pics say more then 1000 words.



Title: Re: 3MA trackbike project
Post by: maccas on May 01, 2015, 12:17:08 PM
I like your approach to these problems Rui. Very logical and you spend alot of time researching. Good stuff!

I also plan to do something similar on my 3xv with a fixed airjet and block the always open airjet in the VAJ blocks allowing me to bleed in extra air when required but running a proper airjet in the carb most of the time.

If you need some 3xv boost bottles just let me know and i'll send you some.

Dan
Title: Re: 3MA trackbike project
Post by: Paul on May 01, 2015, 02:02:50 PM
Sorry. What was I thinking.
Title: Re: 3MA trackbike project
Post by: Edd on May 01, 2015, 05:02:28 PM
Hi Rui

If you just add the air jets that are open at 8000 rpm and use that as a fixed air jet. Just an idea dont know if the jet sizes are hole sizes or area sizes.

Edd
Title: Re: 3MA trackbike project
Post by: casal-fan on May 02, 2015, 12:26:03 AM
No worries Paul ;D

Hi Edd, don´t know if I understand you correctly.
In theori, adjusting TPS output voltage manually to fool the ECU into thinking that throttle is always fully open, will 1)make the ECU run a fixed ignition curve. 2)make the ECU command the VAJ with rpm as the only variable. Now, we know that TPS voltage output specific for full throttle will command solenoid 3 to open between 4-8000 rpm, this is the important bit.

The fixed airjet will affect fueling in the hole rpm range, having the possibility to open an extra airjet, or even maybe having that jet (solenoid 3)as the only one working at all, between 4-8000 rpm, will "attack" the overrich sympthoms quite more or less in the area where it is worst.

At first glance, it would even be more simple then the fixed airjet mod.
With the fixed mod, and in theori, a change in airjet size would implicate a change in main jet as well.
With the alternative here explained, once main jet size is established, then you can alone Work with the air jet controled by solenoid 3 to clean the mid rpm, and be sure that main jet performance would not be upset. In theori ;D
Louis tryed a similar setup, but controled by aftermarket ignition:
https://www.youtube.com/watch?v=EPDIHlehhCA

Dan. I have a couple of 3XV bottles wich didn´t got sold, but I was also keeping them, if needed for the 3MA. I quess it´s whats called being proactive. I appreciate the offer though :)
Thanks for the comment on the logical approach... it´s exactly what scares me a bit. 2strokes and logical, seldom seem to go along ;D
What the heck... it´s all good fun ;D We´ll see how it goes.

Cheers
Rui


Title: Re: 3MA trackbike project
Post by: jools on May 02, 2015, 12:54:34 AM
Watching in anticipation........... :)

from what you are theorising, my use of 12mm spacer/adaptors between reed cage and non standard carb intake for the 32mm 3XV SP carbs might not be such a bad thing  :D
Title: Re: 3MA trackbike project
Post by: Edd on May 02, 2015, 06:05:20 AM
Hi Rui

I was looking at the pic with 8000 rpm line on it. My mistake vaj's work from rpm and not tps.

Edd
Title: Re: 3MA trackbike project
Post by: Louis on May 03, 2015, 11:04:47 AM
Hello Rui,

Your bike is already looking great :)

Quote
Hopefully this enigma will also wake Luis up from his hibernation ;D
Have a bid off low profile because off a new function on my work witch need quit some studding :-[
Over three weeks have my final exam, pass that all is good. And I'm back on my projects
For now I need to focus my self to get this behind my back.

Back to your project and ideas.

-
Quote
Initial setup with fixed  0-1/8 curve, modified pickup for minus 2-3 degrees
Do you use the 1/8 curve with two degrees pickup move?

-
Quote
35mm shorter pipes
Great work, going to do 30mm shorten in frond off the pipes. To (hopefully) mach the 1/8 curve 14 degrees at 10,750

Quote
Left the workshop with #280 mains, #130 air, and still not reving clear (not riding, just blipping the throttle). This with snorkels mounted but cutted at the rings.
Have to find out what´s causing overheating of cyl. nr.1, and then another experiment. 3XV boost bottles.
Don't focus yourself to much on the right side cylinder smoking more then left.
When blipping the throttle they still filling the crack cases you can't clear it enough with giving full throttle on the stand
You need to ride it, let the pipes work :)
Have seen it on my dyno many times, if I change something and worm her up on the dyno the pipes don't smoke equally
Need to let here pull a few times on the role, before I can do a good measurement.

What that problem causes I don't know exact, perhaps the ride side oneway valve is working badly?
If you have the chain mounted, take here out for a spin ones you have cleared the crank cases see if the pipes smoke equally.
I'll bet that problem is solved then

The idea off using the solenoids that closes at full throttle would work fine ;) in fact you can left the unwanted solenoid disconnected it will be all right (as it is closed when not working)

But think this idea comes from your findings now when blipping the bike on the stand giving you the rough/smoky mid rpm section.
Ones you ride your bike on the track it will pass that rough mid section without any problems, the bike wont fill his crank cases in a couple off meters :D
The use off the solenoids are great when you run a road bike there the bike has time enough to fill it self.
Looking at your tires I don't think your 3MA will have any problem in the mid section simply because you wont be in that rpm range that long 8)

Your boost bottle idea (trying different volumes) is a nice one.
You can also flip the carb rubbers ( R to L and L to R)and connect them in the middle with a tube.
From personal findings, this is noticeable.
When connecting them together your mid section is easier to ride. (don't expect a miracle, but its noticeable)

On the higher RPM think connecting them together will harm it a bid (as racers don't have it) perhaps it disturbs the flow or pulses a bid. That is way I have plugged it off.

Ride your bike, and many problem will solve.
Title: Re: 3MA trackbike project
Post by: Need4speed on May 03, 2015, 06:14:35 PM
Quote
Ride your bike, and many problem will solve.
Yep  ;)
Title: Re: 3MA trackbike project
Post by: casal-fan on May 09, 2015, 07:02:25 PM
Quote
Ride your bike, and many problem will solve.
Yep  ;)

And so I did ;D
Shitty weather, wet road, got me bum all wet.

Initial Setup.
WOT curve + 2*, VAJ pluged in giving in total #110 air before 4000rpm - #270 from 4-8000 and Again #110 after that.
MJ - 240
Interconnecting crankcase hoses blocked.

Goes quite OK... only had it to 11-11500, only 520* on EGT, but that Means nothing on just 4-5 km drive.
The pull - wooowwww, it pulls like crazy... I mean like nuts crazy ;D

Hopefully sometime tomorrow sun will shine so I can continue Development.

EDD, same prob as you mate, the bike is sometimes missing responding on throttle input after WOT.
Sometimes I even notice it when changing gears with clutch, nothing for a fraction of a second, and then goes... but then, when it goes... it goes ;D
I read on your thread, that Paul suggested a bit more timing? I can try that setting TPS to 0 curve and adjust pick up to gradually increase or decrease timing and see how it goes.
Also gonna try the 3XV bootles and see if that makes a difference... and of course jetting finetuning.

Clutch is playing a bit, the bike want´s to pull straight away. Cold weather, or maybe not sufficient leverage from the custom chinese lever... will have to look into that.

But, overall quite happy with the first dynamic test.

Title: Re: 3MA trackbike project
Post by: Louis on May 10, 2015, 10:53:02 AM
Good to hear your first drive is a success :) Now the fun starts with jetting your bike ;)

The 240 mains is that with the snorkels in or out?

Hopefully the weather is better
Title: Re: 3MA trackbike project
Post by: casal-fan on May 10, 2015, 12:02:40 PM
Hi there Louis.
The rings on the extremity of the intake tube to the airbox are cut, that´s it.
WOT is not lean, doesn´t feel lean, and EGT numbers don´t seem to point to lean... but that will have to be assured by testing.

But before I can start, I have to determine what is causing the engine not to respond to throttle input after WOT.
Edd wich had kind of the same problem, started focusing on his 3XV, so I think I´m kind of alone on this one.

Last night I did some research on what might cause this:

Frits Overmars writes this about the cagiva500 race bike:
"On a reed-valve engine the reeds are opened by the suction from the exhaust pipe. When you close the throttle, the energy flow to the exhaust stops, and thus the suction stops.
When you open the throttle again, nothing happens because the exhaust suction is absent; the reeds stay closed and there is nothing in the cylinder to combust. So the rider opens the throttle a bit more, and a bit more, and a bit... and then there is enough mixture in the cylinder to start combustion again. But now the throttle is wide open: Whamm, high-sider
!"

I hope this is not my situation because if it is I´m screwed ;D
I have 0.3mm reed valves, this should not be so stiff that crankcase depressure alone could not open them. It worries me a bit though, that for a fraction of a second it feels like the engine really just stopped, there´s no BBBWWOOOO, nothing. the engine is just not there.

First plan of attack is to chance inlet specs by plugging the 3XV bottles and see if it helps.

We´ll see how it goes.

PS. If anyone experienced this kind of problem, on 3MA or any other bike input is much welcome ;D




Title: Re: 3MA trackbike project
Post by: Louis on May 10, 2015, 12:39:43 PM
Quote
I have 0.3mm reed valves, this should not be so stiff that crankcase depressure alone could not open them. It worries me a bit though, that for a fraction of a second it feels like the engine really just stopped, there´s no BBBWWOOOO, nothing. the engine is just not there.

Interesting ???

Seems to be a problem with 3MA's that are revving more than the stock 10.000rpm as the stock bikes does not seem to have that problem

The story Frits describes is known to me (also described on Dutch forums) but TZ250's does not have that problem.
Example the TZ250 U (similar to the 3MA) haven't got that problem with dropping dead on high rpm

The ignition does not seem to be the problem (3MA CDI has no restriction in that rpm range) also Edd uses a ignitech and has the same problem.

Also I asked Edd if the RPM meter drops when it accured, seems not to be the case. (If you can check that to?)
The only thing I can come up with now is that perhaps the 3MA coil gives problems (witch you and Edd are using if I'm correct)

Need for speed is using TZ stuff/ignition and does not seem to have that problem. (don't know how high he is in the RPM range)
Perhaps its something with the 3MA coil, Its just a guess. (But i doubt this)

It could still be fueling.

Does the problem is there to when you hit the problem zone in second, third, and fourth gear?
If its only there in fifth and six gear on a longer wide throttle part, sound like you run out off fuel


Title: Re: 3MA trackbike project
Post by: Need4speed on May 10, 2015, 01:20:27 PM
https://www.youtube.com/watch?v=0o-WaHZ_HxE (https://www.youtube.com/watch?v=0o-WaHZ_HxE)  ;)
Title: Re: 3MA trackbike project
Post by: maccas on May 10, 2015, 01:47:14 PM
I get a similar problem on my 3xv but i get a bit of blap blap blap with it so i think it is overfuelling in my case, when i go back to full throttle there is a pause then it comes on again as strong as before.

I'm putting it down to closing the throttle (in my case to about 30-40%) with the same engine speed, so there is a brief moment where the air accelerates under the carb slide, lowering the pressure and hence sucking harder on the fuel in the float bowl compared to the WOT case. I know the needle will reduce the fuel flow passage but i bet it sucks pretty hard and pulls alot of fuel through.

3ma's are known to have part throttle fuelling problems, Warwick has used a smaller q-4 needle jet to counteract it, i know that is with snorkels removed.

To sum up, i'd try lowering the needle Rui.

Dan
Title: Re: 3MA trackbike project
Post by: casal-fan on May 10, 2015, 08:13:12 PM
Dan
I agree with what you write. Valid input there. Thanks.
As I see, it and it´s only my opinion, this needle thing is a big pain, and I focus, or have focused a lot on this, and got acceptable results by increasing needle diameter considerably... but 3MA is a pain to change needles ;D, so I just dropped them all they could drop, theyr already as low as they can be.

Need4speed. Good vid. impressive. Is that std. gearing, and 1st gear WOT pass?

Louis.
The hesitation is (was ;)) just when shifting, and then it would not be power for a fraction of a second. The bike revs a bit over 12000 on the tacho, with power from about 8000rpm, this at full throttle, no hicks, over 4000rpm of very good usable power.
I  disagree a Little bit  with you about the TZ U - Intake area is quite different. I think this has major impact on engine behaviour.
First, the 38mm carbs will behave different, and then intake rubbers are considerably longer.

The news.
Just reporting, now I have to analyse what is what, and continue Development from there.

Boost bootles - hesitation problem shifting gear - almost solved. Only when using a bit more time shifting with clutch, maybe still a bit or hesitation, or maybe just my brain playing tricks. Fast, No clutch shift, is like  seamless transmission - it just goes.

Main jet almost established. 1-5 gear wot pass, cutted ignition, after having punished the beast for 2-3 km. showed 605*C on EGT. OK if it was 6th gear max rev, but a bit lean just 5th. Plug chop also showed a tad lean, but the best news were, both plugs read exactly the same ;)

Tryed 0 curve with 2 degrees retard - not good, bike did not like that.

Top end is VERY good, now focus goes to make the bike Work at all throttle range and all rpms... if possible.




Title: Re: 3MA trackbike project
Post by: Need4speed on May 11, 2015, 07:25:38 AM
Quote
Need4speed. Good vid. impressive. Is that std. gearing, and 1st gear WOT pass?
It's start from 2.nd.gear going to 3 and 4...with a Iphone in left hand  ;) after that decide to get a GoPro  ;)
Title: Re: 3MA trackbike project
Post by: Edd on May 11, 2015, 07:58:02 AM
Hi Rui;

I also get the hesitation when shifting gears usually into 4th and 5th when on main straight. Nothing gets rid of that hesitation not even advance as I am running a TZ curve at present max is 32 degrees. I thought it was squish; fitted a head gasket no diffrence. Thought main jets nothing 280 to 220 no change EGT registers slightly higher 1100 deg ferenheight with 220 fitted. I am still on fuel starvation at this point as no other changes have yielded any results. What I have picked up at red star is that when going into the corner after a straight if i dont blip the throttle the response is better when getting onto the throttle again.

The other thing that can also cause this is Power valve :o I have managed to get the hesitation from very bad to tollerable by just playing with PV map settings.

I have also realised that if I change gears in the straight at 12 000 rpm no hesitation but below that the hesitation surfaces. Need more time to verify this statement.

Edd
Title: Re: 3MA trackbike project
Post by: casal-fan on May 12, 2015, 01:50:50 PM
Cheers Edd.

Is your bike acting similar to this:
https://www.youtube.com/watch?v=yG7xQYvCXmQ
Title: Re: 3MA trackbike project
Post by: Edd on May 13, 2015, 08:46:02 AM
I will have a look at the video when I am home ;) Cant acess youtube where I am at.

Edd
Title: Re: 3MA trackbike project
Post by: Paul on May 13, 2015, 01:01:07 PM
What size pilots are in there Ed? Does it ever give starting problems?
Title: Re: 3MA trackbike project
Post by: Edd on May 14, 2015, 09:21:16 AM
Starts first kick think 17.5 or 15
Title: Re: 3MA trackbike project
Post by: Paul on May 14, 2015, 09:45:39 AM
Not that then.
Title: Re: 3MA trackbike project
Post by: casal-fan on May 14, 2015, 02:33:26 PM
Don´t know if it is relevant, but A LOT of the vids I looked at, 3MA track riders simply do not blip the throttle. Maybe it´s a jap thing, don´t know.

20 minutes without blipping once.
https://www.youtube.com/watch?v=na60_NTtDPo

I gave it a bit of thinking over the last few days.
Basically the bottles improved behaviour, and more advance worstened the bike.
Next testing will go in the direction, of tamming impulses to the carb a bit more by adding larger air jets (and compensate as (if) needed with larger mains, as well as reducing advance a tad (full throttle curve from +3*)

Not as severe, but a bit of this when trying 0 curve.
TZ CDI (advance)
https://www.youtube.com/watch?v=TzZJ7mBOFtw
Title: Re: 3MA trackbike project
Post by: Edd on May 15, 2015, 08:26:51 AM
Hi Rui;

Still havent had time I am sorry but preparing a 3xv for 23rd Phakisa and I am running behind ;D Last minute racer :D shit just had too much on the plate. But will get back to you Long straight at Phakisa 10 sec in 6th gear befor breaking will be nice to see what the bike does.

Edd
Title: Re: 3MA trackbike project
Post by: Edd on May 15, 2015, 03:03:46 PM
Hi Rui

Mine is much worse than in the video. It is frustrating putting the anchor out on the apex. Its like a lean symptom you get on the cable Baaaaaaaaaahhhhh back of the cable 1/8th throttle wait for it; wait for it; and it will go gagagagagaga then all of a suden 49 bhp 12000 rpm is up next gear as if nothing is wrong and of I go till the end of the next straight. Also if I push the bike like in the video I will not get the hesitation when changing gears on shorter tracks longer straights I still get it into 5th.

Edd
Title: Re: 3MA trackbike project
Post by: casal-fan on May 15, 2015, 07:56:03 PM
Cheers Edd.

Ok, thanks for your response, I kind of am in the same situation as yourself, because I really would like to have a good calibrated bike for the already booked first trackdays of the year.
I sendt you an e-mail, look at that, maybe a good insight.

Today, I also got some time to do some testing.
Since I couldn´t find defenitive testing from 3ma owner on how exactly the VAJ works, I decided to do my own.
My plan was to set TPS to a fixed curve, plug a bulb (instrumentation light ;D) to solenoid, start the bike, and find out when it was opening and closing. I thought this way I could set some RPM numbers on the yamaha graph. No good, solenoids are NOT doing what they graph says they should be doing. (se pic)
I lost a lot of time with this, checking if I had everything rigged up correctly and so on. No definite conclusion, I´ll have to think about, and see if I was doing something wrong...
I looked into Louis reserach on this... and from what I can see, his findings don´t add up to the graph yamaha shows.
I read once, that when yamaha brought YPVS to light, they made sure to bring the 500GP bike out of the pit so everybody could see it, and then had the ypvs running backwords, just to confuse the opposition ;D
Maybe something similar with the air correction system ;D

I rigged up the VAJ with std. jet sizes, upped the mains to #270, full throttle curve +3* advance.
The bike run, really good. After it warmed up, and cleared the bababappprrrrbabaprr, good throttle response, good power, good pickup from part throttle, good maintainence throttle, but lean on main.
And then I noticed... THE CHOKE WAS ON :o
Closing choke worstened everything, I didn´t even try, just rode back to the garage.
Will have to look into this, but it would be interesting to see how the bike acts by reversing the air correction stuff, meaning less air in the mid range, and more at full tilt. Another thing is that I might have rejected the fixed air jet solution, a bit to fast.

Also, cyl1 has about 1mm more float height then cyl.2 wich is set at 5mm, it´s floading, will have to look into that.

It takes time to figure this 3MA out... I hope I can do it.

Title: Re: 3MA trackbike project
Post by: Louis on May 15, 2015, 10:57:16 PM
Hi Rui,

There could be some differences in CDI's (3ma00 or 3ma01) regarding the airjet opening sequence.
It is still on my to do list to read out the airjet controls sequence on my test bench.

Still thinking with you, your hesitation is it that strong?
I mean do you have full power back after your dip?(like after 1 sec)

Is it something like this, but in your case in a higher rpm range?
https://www.youtube.com/watch?v=Wpx9XlVjhfs (at 2 sec)

Regarding jetting. It wont be that easy to clear the trouble some at a 3MA ;)

Perhaps you can try this setup:
http://www.tzr3ma.com/experimental--track-bike-1-.html
It leafsout quit some variables out. Perhaps you already have all the parts in your workshop

Just a idea
Title: Re: 3MA trackbike project
Post by: casal-fan on May 16, 2015, 12:41:54 AM
Yes Louis, there are maybe differences in the way the different ecu contrl the solenoids, but I have a 00 cdi, and the chart appears in the 00 manual... so I don´t know...

Louis, with a more or less correct full throttle jetting, running full throttle from as low as 5000-6000rpm is not a problem.
This tells me that the fundaments (pipe, cylinder, reeds, kompression, squish, etc etc) are good.
 The problem came a bit when changing gears up. then the engine would "dissapear" for 1/3 of a second, and then come again with good power. Also blipping the throttle on downshift, it would not be able to do that. I like a blippi engine ;D.
Now. It seems the problem with upshift gets worst with leaner full throttle mixture (also, Edd reports that if he keeps the engine running high RPM for a long time, the problem is not so bad. Maybe longer time full throttle gives a richer mixture).
On my case, I know this because 605*C EGT almost gives no problem, but 630*C EGT, gives the problem.
It feels a bit the same with blipping on downshift. No response when lean, and response when not so lean. (but will have to test more).
But 0-½ throttle feels very vague. Not crispy. It could of course also be, that is the caracteristic of the engine off course. I once had a go on a full sugaya kitted VJ22. I did not like it very much because it simply did not pull before 8000rpm. The owner said, that is just engine caracter, its like that.
Time to test is very limited... I take some "escapades" to the workshop and try some setup, then no more time, and at home I try to understand what is happening. Not the ideal scenario, but it´s what I have.

Your hik video.
Now you mention it. There has been some circunstances where an occasional hik appeared on my bike. But, your video.
At first I thought... that seems like a lean hik. And then I thought, let me tjek another of Louis videos ;)
Point being RPM. What happens in both videos at about the same RPM
https://www.youtube.com/watch?v=7L8VwKOCLRQ

Changing nozzle... Jehh, I´ve looked at what I have. I have TM nozzles, but they are very different to the nozzle om the 3MA.
But, interesting what you did. I´ve been reading a lot about different carb components in the last few days ;D

Think I will have to turn focus again to simple, and read the signs in a simple way, thinking about the foundaments of jetting. Kind of been forgetting that with this VAJ story, when I don´t even know for sure what they are doing.
We´ll see how it goes...

Cheers
Rui

Title: Re: 3MA trackbike project
Post by: casal-fan on May 16, 2015, 07:33:47 PM
Another report.
Getting there, step by step.
Changed configuration of the air correction. VAJ2 was blocked, middle #130, and VAJ3 #60.
First outing with #290 mains. - Quite good.
Tryed several cenarios of different throttle openings, at different rpm, blipping, aceeleration from different throttle openings to full throttle. The bike behaved very good. Overrev to 12500, and felt still a bit lean on top.
EGT started to act very predictable, climbing slowly on full throttle, but still reaching quite high temps. 640*C
Tryed having solenoid 3 operating with solenoid 2 input just to see how it went... not good.
Changed setup to #300 left / #310 right (the right pipe was hotter), and then it started to rain :(

How it is now... I would ride it and it would be a fast, easy bike to ride.

This setup now just needs a bit of refinement.
Have 2 options - 1-larger mains 2-smaller air correction. But before I try nr.2 I have to know for sure what the solenoids are doing (that´s the next test)
Option 1 - larger mains, I can try soon, but I feel that at this point the airjets would be a better finetuning tool.

IF SOMEONE  HAS A PAIR OF #100 AIRJETS HE CAN PART WITH, I would buy them, or even other sizes.
Alternative is to start making my own, but I have no idea what the hole sizes are equivalent to in mm.

Cheers
Rui
Title: Re: 3MA trackbike project
Post by: Paul on May 16, 2015, 08:52:07 PM
Rui
I merely soldered the Jets and hand "reamed" them with a drill bit. It's only air.
I would say... After 9000 I wouldn't run more air than 1.2mm. In fact your bike should run fine with a 1.2 fixed air jet, fitted to where the solenoids go into the carbs, all the way through to 12500.
I ran long pipes and cable tied them where I could change them easy.
Watch it cause they seize very suddenly and it's always when you are "making progress".
Title: Re: 3MA trackbike project
Post by: paul8899 on May 16, 2015, 08:57:13 PM
On mine I filled the holes up with JB weld and re drilled them.

I found a list of jet sizes on the allens performance site http://www.allensperformance.com/jetsizeconv.html I don't know if the air jets are the same as mains though. On mine I ended up opening them up in .1mm increments rather than by jet size.

It's interesting to see how you are getting on with your experiments :)

Are you running yours with the airbox snorkels removed ?
Title: Re: 3MA trackbike project
Post by: casal-fan on May 17, 2015, 11:09:02 AM
Hi Paul8899.
I´m running snorkels, but with the extremity where the ring is cutten of. This is how I got the bike, and really haven´t bothered trying something else. It doesn´t feel like power is a problem with the snorkels like this.

If possible I would like mikuni air jets. I know its just a hole, but it would be nice to have the correct numbers on them, and test them, to get a more correct picture of what the engine is wanting.

Paul, I agree with you about the "smaller" jet on the high rpm range.
I think I´m not that far away from a fixed jet setup, with the setup I have now. VAJ2 is blocked. VAJ3 is a tiny #50, that according to the yamaha chart id doing this ( __---------__ ) meaning its open in the midrange of the rpm.
Like I wrote, I´m getting a bulb plugged to vaj3 and watch what it is doing on real live.
Another indicator is that for the last run, going from #270 to #290 did not make that much of a difference, this could mean that air correction is too much, for a relatively small change in main jets to have significant impact.

Thanks about the warning ;D
Yeah, it would be a shame to blow it.
I have some things in mind though. keep an eye on egt for irregularities, and I abort a run straight away if something doesn´t feel right.
These 2 videos kind of sumarise it. It´s like the good engine and the bad engine :D

The good engine as I call it runs over 230km/t, has the sound of a bee on steroids when in the best rpm range, and the max power range can easily be defined by that very strong buzzzing sound.  In this kart setup it´s from 12-13.5 RPM.
EGT never higher then 640*C on the long straight, 6th gear, and no irregularities on temp. rising or falling.
Won the race.
https://www.youtube.com/watch?v=dCfalwm3Rqw

The bad engine.
It revs to the sky, but with less torq (or at least it seems), sound is more like a bee, that forgot to take the steroids ;D
EGT gets to very high numbers, and it´s kind og irregular in its climbing, sometimes it even gets colder.
Best exemple at 9.09 when Cyl.2 goes from 680*C to 250*C and then it ceases.
Some would say deto, robbing heat from the exhaust.
Didn´t win the race.
https://www.youtube.com/watch?v=z7D2B1DQ6_c
Title: Re: 3MA trackbike project
Post by: Louis on May 17, 2015, 11:48:08 AM
Looks like you are going into the right direction ;)

https://www.youtube.com/watch?v=7L8VwKOCLRQ
This video is from a 3MA3 engine, so it could be having a different opening sequence off the airjets.

Quote
Another indicator is that for the last run, going from #270 to #290 did not make that much of a difference, this could mean that air correction is too much, for a relatively small change in main jets to have significant impact.

Bingo, The airjets do open an enormous amount off air.
Therefore (I think) fiddling around with the needel height with the use off airjets can't hardly be noticed.
Also Needlejets and mains changing do not give you the natural feed back.

Still think for a track bike, best is to go to fixed airjet
-airjet in hose connected on original point
-airjet in the carb belly (this could be giving slightly different behavior then outside the carb belly)

I know some have different point a fews about the snorkels ;) (and or cut)
Personally I have good results with leafing them out (even cut they have a small diameter) This would give you no problems in the mid rpm range but on the higher rpm I doubt if they give enough (specially if your around the 11000rpm mark)

I could be a nice experiment on the EGT 8). Leaf the mains un touched only flip out the snorkels and see what the temp does.
Of course react if its going to quick to far :o

Nice bikes he, those 3MA's ;D
Title: Re: 3MA trackbike project
Post by: 41juergen on May 17, 2015, 01:41:29 PM
Hi Rui,
not sure if that may help you, but you may have seen the data I got out of the 3XV CDI's. None of them (either the -00 nor the -40) have the air jet behaviour as shown in the manual. So don't trust whats the jap. engineers showed us in the papers....  ;)
wbr
Juergen
Title: Re: 3MA trackbike project
Post by: casal-fan on May 17, 2015, 08:29:20 PM
Hi Juergen.
I´ve looked. Great project you have going on there.
Juergen I also found that is the case with the 3MA. The first readings I took were nothing like what was supposed to be expected (see picture above in this thread), and today I could established without a doubt that:
On 00 CDI, on the full throttle curve - VAJ3 is opened from 0-8500 RPM, and closed until at least 12500 RPM

Louis, I got the proof about the little difference on MJ changes with the VAJ hooked up.
I had the bike set with 300 - 310 MJ and a total of 190 air until 8500rpm closing to 130 after 8500rpm.
The plugs showed VERY little sign of being more rich, virtually nothing. (Test taken 2 charges up the road on WOT 1-6 gear)

So, the next test (I didn´t have #100 jets), so I rigged up the bike with #60 always open and #50 closing at 8500.
Not good, the bike simply would not pass 8500RPM. It was obvious, (also because I had a bulb showing when VAJ3 closed), as soon as it did, BRRRRAAAAAAAAAAAAAAAAA, would simply not pass 8500RPM

So... next step, was to try and find out the sizes of the air jets. I had a 1.5mm drill, a 130, and 160 jet. the drill woudn´t fit the 130, and clear with a rather snugg fit the 160. So It was obvious airjet sizes are metric.
Borrowed a 1mm drill from a friend, filled the 160s with tin solder, and drilled them.

Setup was at this point 300-310 MJ, 160 under 8500rpm and 100 after.
Now... What can I say... it´s not a bike, it´s magic.
Not gonna say, this is the best setup, because I haven´t tryed other setups closed to this one, like one size up or down on air, etc... but as it is, wow... what a machine.
As soon as the engine is above 6000 rpm, a minimal throttle input is felt straight away, in all throttle ranges, opening the throttle full, feels like a couple of rockets have been litten ;D, and it doesn´t stop until about 11750-11800. After that still good overrev range.
Transition VAJ3 open/closed is not to feel.

Focus now goes to the rest. Gearing is too short at 14-45, clean up the wiring, retorq nuts, a couple of spray cans for the fairing, etc...
I´m happy ;D
Title: Re: 3MA trackbike project
Post by: Louis on May 17, 2015, 09:29:51 PM
Quote
Louis, I got the proof about the little difference on MJ changes with the VAJ hooked up.
I had the bike set with 300 - 310 MJ and a total of 190 air until 8500rpm closing to 130 after 8500rpm.
The plugs showed VERY little sign of being more rich, virtually nothing. (Test taken 2 charges up the road on WOT 1-6 gear)

That is completely right :)
At WOT you creating a fixed airjet mode as the airjet's  (in your case) is closing at 8500rpm giving you a 130 at WOT
Witch will be the same in my case with a fixed airjet of 130. (at WOT of course) ;)

What I mend is:
That with the use off the controlled airjest in the mid rpm section the needle height or needle jet (even mains) can't hardly be noticed as the airjest are opening closing in that whole rpm range leaning/richen the engine enormous.

Example: Here you have a testrun with a relative stock setup.
You can see the leaning off the airjets quit well.
(http://www.tzr3ma.com/images/EPSON001.jpg)

Quote
opening the throttle full, feels like a couple of rockets have been litten
That's the famous 3MA ''kick in the arse'' ;D

Title: Re: 3MA trackbike project
Post by: maccas on May 18, 2015, 10:27:28 AM
Great stuff Rui!

I'm thinking this might be similar to what i'm experiencing on my 3xv. The airjets are too big, changing main jets on the dyno was hardly making any difference to the afr readings at the top end.

Allens performance in the uk sell the airjets if you wanted to buy them.

Dan
Title: Re: 3MA trackbike project
Post by: Edd on May 19, 2015, 10:29:03 AM
Hi Guys

Quote
Setup was at this point 300-310 MJ, 160 under 8500rpm and 100 after.
Now... What can I say... it´s not a bike, it´s magic.

So Casalfan is running this setup at sea level with std airbox on normal pump fuel. Sounds about right mine was at altitude with 260/270 mains and bike was excellent with fixed airjet 120.

It is very difficult for me because of the mods I have done to my track bike. It just moved the bike into an uncontrolled environment. I am running 220 mains with 120 fixed air jet bottom half of airbox which I am going to remove for my next experiment open carbs. EGT is registering 1100 deg ferenheit. Which is way off what some guys are mentioning as controllable figures.

Edd
Title: Re: 3MA trackbike project
Post by: casal-fan on May 19, 2015, 06:06:10 PM
Louis, don´t misunderstand me. I love simpel ;D
But from my experiments, in my bike, (and this is important because I have a setup that makes the bike can not be treated as original anymore) I feel like it wants leaner, amybe just a little bit between 6000-9000 rpm, and it wants richer then the carbs are giving, after that RPM.
Now, how could I make this happen with a fix airjet? I know that a #60 airjet will make it impossible for the bike to rotate more then 8500rpm, and I know the #100 airjet is still making the bike quite lean at top RPM.
I will have to test to see, but if I test, I would start with 100 fix airjet, and take attention to the midrange, if it was better or worst.
But with 160, I have a very good midrange, and then after 8500rpm, with 100 air, I am still a bit lean at top RPM.

The VAJ is there. We have found out a little bit how it works. If it can be used to improve performance, then use it, but first one has to understand what it is doing.
In my setup, (and I´m still going to test this), but if VAJ2 closed anywhere between 9000 and 11000 rpm... then I belive I could improve the engine quite a lot more by dividing air correction after 8500 rpm with the 2 airjets. Actually I´m REALLY looking forward to see if this can be done, still using the full throttle curve.
My impression is that with these carbs, air can be used with more impact, then main jets or needle, just like you said Louis.

Dan.
That also seems to be happening with my 3MA.
Actually I tryed playing with airjets on my 3XV a bit, having the yamaha chart as reference. Not good, did not do what I was expecting it to do. But Juergen has also proved that the yamaha chart that shows what VAJ is doing, may be incorrect.
Wemoto also has airjets, and I have to order sprockets again... 14-45, gives me 12000 rpm in 6th in about 300 meters.

Edd
Mods is a dangerous thing.
I have been working on a bike for 3 years, it has a lot of mods. I´m not finished yet.
Still belive you should try richening your bike in the top rpm range. EGT, I think is a number that tells you nothing. But combine EGT with a plug chop, and then you can use the EGT numbers because now you have a reference.
For my bike, what really helped with better throttle response was the boost bottles. But that was while experimenting different things, maybe the bike behaves good without them now. Don´t know
Edd, you can have zeeltronic operating your VAJ. Try that. Who knows. If your bikes behaviour is something like my bike, you would need more air in the mid. RPM, and then gradually less air. But, again only my opinion...
And another thing Edd, my bike does not like too much advance.
Title: Re: 3MA trackbike project
Post by: Louis on May 19, 2015, 07:43:35 PM
Quote
Now, how could I make this happen with a fix airjet
Well, a fixed airjet does not make it leaner in your trouble zone that is for sure :)

Of course you can try to find a mach with the controlled airjets to fit your needs. But they open just a huge amount off air to lean out your trouble zone witch is difficult to control (as how much are you leaning it ??? )

I would try a smaller needle jet. in Combination with a fixed airjet (that improves it quit a lot) You can use the Q4's from a 3MA3
Stock they have Q8 or Q9 so you leaning the bike quit a bid in the mid range using the Q4's

The advantage off using a fixed airjet is that all other changing's to the carb making more sense.
(As you have less variables)

Also been reading that it is easier for a controlled airjet to lean a carb than to richen it.
Has something to do with the size off the fuel particles in the mixture tube.
-More air = more smaller fuel particles which are reacting faster (to adapt to the speed the mixture is going inside the tube)
-Less air = bigger fuel particles witch reacting slower (to adapt to the speed the mixture is going inside the tube)
Just some info, perhaps you already know it.

Try to score some Q4's or perhaps you have already something lying around ;)
Title: Re: 3MA trackbike project
Post by: Louis on May 19, 2015, 07:48:51 PM
Quote
which I am going to remove for my next experiment open carbs
That will be great Edd, it is my next step to. (on my test bike)
After having tested the shorter pipes to mach the 1/8 curve. (see what that brings)

Next will be open carb's, I really expect better results with the use of open carbs.
Would be nice to see/here your results on that to
Title: Re: 3MA trackbike project
Post by: casal-fan on May 19, 2015, 11:28:11 PM
Quote
Now, how could I make this happen with a fix airjet
Well, a fixed airjet does not make it leaner in your trouble zone that is for sure :)

Of course you can try to find a mach with the controlled airjets to fit your needs. But they open just a huge amount off air to lean out your trouble zone witch is difficult to control (as how much are you leaning it ??? )

I would try a smaller needle jet. in Combination with a fixed airjet (that improves it quit a lot) You can use the Q4's from a 3MA3
Stock they have Q8 or Q9 so you leaning the bike quit a bid in the mid range using the Q4's

The advantage off using a fixed airjet is that all other changing's to the carb making more sense.
(As you have less variables)

Also been reading that it is easier for a controlled airjet to lean a carb than to richen it.
Has something to do with the size off the fuel particles in the mixture tube.
-More air = more smaller fuel particles which are reacting faster (to adapt to the speed the mixture is going inside the tube)
-Less air = bigger fuel particles witch reacting slower (to adapt to the speed the mixture is going inside the tube)
Just some info, perhaps you already know it.

Try to score some Q4's or perhaps you have already something lying around ;)

Yeh, I would like to try different configurations, but, it´s hard because of the limited time, budget, etc...
Thanks for the insight on your research on air correction, I will for sure keep that in mind when I continue.

Actually, to be honest, I already had taken out from one of my boxes in the workshop, a pair of TM34 I used on another bike for some years ago, in case I could not find a decent setup with the 32mm original carburetors ;D
Now, I kind of like playing around with the 32mm though, and go a bit deeper in researching about how the VAJ operates, and how they affect carburation.
Louis, my biggest problem now is the bike being a little bit lean at full throttle, max rpm. This is with only 1 airjet open - #100.
Also belive that upping main jets will not bring the wanted results. (I have something in my mind that Warwick wrote, that is  on his 3MA, he continued jetting up to around #400 main jets, just to get a safe reading on the plugs).
If my hunch is correct, to get the engine a bit more rich at full rpm, full throttle, the way to go is: going below #100 air jet.
But then another problem can happen, and that is the bike can not come over the rich spot at 8500-9000 rpm.
This is why I wrote that I can not see how a fix main jet would help. But, I would have to try it to be sure.

Louis, there is something in your dyno print, that caught my attention for some time now.
It is the disturbence on AFR at about 9750 rpm. The mixture goes a bit richer. It can be many things, but if this happens because the VAJ2 with the little #50 airjet on stock setup, closes... then I can try to correct carburation even more on my setup.
I could go from the 160---100 at 8500rpm I have now,  to maybe 190---140(8500rpm)---80(9750rpm)  This setup (or something similar), could in principle lean the rpm range where the mixture goes rich (8000-9000rpm) and make it richer in the higher rpm after 9750.
I know that this is going away from simplicity... but hey... my parents tell me that when I was a kid, the first thing I did when I got a new toy was to dissasemble it, just to see what was inside ;D... just to say, I can´t help myself digging a bit more into this airjet stuff ;D  ... but not too much. Bike is already booked for tracktime, and 2 races (club level, nothing too serious) the 12th and 13th of June.

Another thing to have in consideration in this party, is what the actual number on the airjets translate in area.
The little picture below can give an idea, why a 3MA can be totally messed up, alone by getting it wrong connecting the solenoides, or putting the wrong airjets in the wrong slots.

Cheers
Rui
Title: Re: 3MA trackbike project
Post by: maccas on May 20, 2015, 12:22:53 AM
Rui,

Have you thought about the powerjets in the 32mm carbs? Could you increase their size to richen it up at the top end? This should leave part throttle mid rpm fuelling pretty much the same.

Dan
Title: Re: 3MA trackbike project
Post by: casal-fan on May 20, 2015, 12:32:53 AM
Rui,

Have you thought about the powerjets in the 32mm carbs? Could you increase their size to richen it up at the top end? This should leave part throttle mid rpm fuelling pretty much the same.

Dan

Dan, haven´t even located those.
Where are they?
Title: Re: 3MA trackbike project
Post by: jools on May 20, 2015, 12:38:10 AM
Hi Rui

Just a thoughtv - going back to your comments on VAJ operation and your "bulbs"

The solenoids have a permanent positive feed (I think) and and the return is switched by the CDI to control them.
Therefore if you connected the bulb across the return wire to earth the bulb will be on and turned off when the solenoid is switched.

If you have not considered this, it may account for the solenoids not appearing to work as expected ?
I'm not sure if the the solenoids power up to open or close the VAJ as I have not studied this.

In terms of correcting the weak full throttle mixture - have you considered trying a different needle ? I know they are a pain to change which is why I have fitted 3XV 32mm carbs. with the std VAJ but I have not tested the bike yet.

I have been reading this thread for tips........ ;D
Title: Re: 3MA trackbike project
Post by: maccas on May 20, 2015, 11:15:46 AM
Rui,

I can't find a pic :-(. They are located under a brass dipper tube when you remove the float bowl. The dipper tube has a slotted head and is about 15-20mm long. Remove that and the tiny powerjet lurks under there, they can be a bugger to get out so be careful. Soak in wd40 or similar and give them a sharp tap with a screw driver fitted in the jet.

Should be a #20 jet, they really are tiny things!

Dan
Title: Re: 3MA trackbike project
Post by: Edd on May 20, 2015, 01:20:17 PM
Hi Rui

Like maccas says be careful removing those they strip easily. I have tested up to a 40 size jet and it didnt have the effect it should. I just canned it and left originals in place. But I must add that was right in the beggining of set up while I was still changing air jets. Maybe with fixed 120 air jet I should give the 40 jets a go again with the smaller 220 mains and open carbs, as the bike is much better now than a year back.

Come to think of it the lean symptoms can be from a too small power jet. ?:-|

Also what Jools is saying you may get open close reversed and that can cause problems. When the solinoid clicks it is closing that jet If I remember correctly. :-[ I did it a very long time ago.

Edd
Title: Re: 3MA trackbike project
Post by: casal-fan on May 20, 2015, 07:04:56 PM
OK Dan, thanks... I´ve seem them, but no time to play with those for now.

About the solenoides. Thanks for the info on the solenoides Jools, but  my understanding on electronics is very close to nothing.
Please elaborate on your explanation, as if you were trying to explain it to a 3 year old ;D
Today, I drove to the workshop after work, to do some more testing on the solenoids.
I have the bulb wired to both wires on the solenoid. With the bulb on-solenoide is open, bulb off-solenoide shut.
This I tryed to the best of my ingenuity, by passing compressed air through the air feed to the solenoid block, and feel it coming out of the airjets.
Then I went out for a ride to see at wich RPM range solenoid 2 was opening/closing. Bulb test showed exactly the same caracteristics as solenoid 3. Both are open until 8500-9000, and closed after that... so, I´m starting to think I´m doing something wrong???, but what, I have no idea. ?:-| (This with TPS showing 4.15V output)
I have ordered 4 airjets in #80, maybe I have time to test, and tailor them a bit... but, like I said... it´s very OK, as it is, and time for testing more is now quite limited.
Title: Re: 3MA trackbike project
Post by: jools on May 20, 2015, 10:12:00 PM
basically if you are confident when the valves themselves are open, that is the main thing. the bulbs are indicating a change of state.

The way you have it wired the valve is closed when light is on, closed when off. Its just opposite to what you might expect to see as the bulb will only light when there is a voltage difference. when the solenoid operates there is no voltage difference across it. hard to explain to a 3 year old.... ;D
I will try and do a sketch.
Title: Re: 3MA trackbike project
Post by: casal-fan on May 24, 2015, 12:18:50 PM
Home all day yesterday, nursing my 6 y.o. daughter, who´s sick.
Had to change weekend plans. She got to play a lot with her favorite gizmo, (the Ipad), and I got the chance to do a bit more research into this carburation stuff...
Not because my bike can not be ridden as it is, it´s actually quite good, but for the sake of more info and knowledge about this stuff.
So.
It has been clear for a while that the configuration of the 3MA carbs, is quite similar to PWK keihins. Meaning, it might say TM om the carb, and looks like a TM carb, but the insides are a lot different from what you get when you buy a TM from a mikuni dealer for exe. Major difference, the emulsion tube, Primary type for regular TMs, bleed type for the PWK keihins (wich seem to be regarded as a very good carb for 2 strokes.)
Another area of research, was (and I hope I won´t get expelled from the forum ;D), the RGV.
Having, very similar carbs to the 3MA, also with an electronic air correction system, it has been a while I´ve been wanting to look into them as well.
As impressive as it might seem, there are quite a few "similarities" in problems found both in RGV and 3MA home-pseudo tuners bikes.
Another reason to look into RGVs, is because there is an "hot-it-up" manual, that describes the process.

First I got into researching PWK carbs, and how they work.
Basically, the general rules for carb. tuning apply to them as expected.
Notice in pic., that keihin states a smaller airjet will make mixture richer.

Then for the RGV...
Air correction system in those, seems to work prety much as the setup I have now on my 3MA, aside from a minor difference at quite high RPM, (wich is not important to me anyway). Basically, on the hot up manual for RGV, the air correction distribution is #100 before 9K RPM and #50 after that...
Notice that the RGV manual states that a larger air jet will make mixture RICH ?:-|
First, I thought... well, what´s to expect... this was written by suzuki people ;D, doesn´t seem to make sense.
For instance, it is commonly accepted that on carburation systems with fixed pilot air jet instead of airscrew, more air, works the same way as opening the screw, letting more air by, and thus leaning the mixture.

Anyway... all this stuff, made me think of another "plan of attack" for testing.
I have no idea if I´ll have the time, but more on that if I do find time for it. we´ll see.
Also would like to try and test the fixed airjet solution. Think I discated that a bit too soon
Another area that seems to pop up, is the throttle slide... too lean on 3MA, maybe? And this is just a note, but it might have significant impact on engine performance ...
The saga continues...
Title: Re: 3MA trackbike project
Post by: maccas on May 24, 2015, 01:03:01 PM
I always thought that the standard tm's were almost identical to the way the pwk's work Rui, primary style air bleed? No holes in the emulsion tube, with the airjet being piped straight to the tip of the needle jet.

Dan
Title: Re: 3MA trackbike project
Post by: casal-fan on May 24, 2015, 03:13:07 PM
Jesus Christ Dan.
What´s up with youguys??? ?:-|
You were supposed to say, yeps, try that, It´ll work good... and then it would work. Not putting more wood in the confusion fire ;D ;D ;D
No, he he... joke aside. Your right Dan, it seems like only the 28mm PWK uses a bleed type, and others have fixed emulsion tubes, just like TMs and TMXs probably as you say. Thanks for clearing that up.
http://www.keihin-na.com/assets/1/7/pwk_parts.pdf
We´ll see...

An now for something tottaly diferent...
http://www.yoshimura-jp.com/en/products/engine/yd-mjn.php
https://www.youtube.com/watch?v=D_kI1m-V06M

Cheers
Rui
Title: Re: 3MA trackbike project
Post by: casal-fan on May 26, 2015, 08:17:14 PM
While waiting for new gaskets for the pipes (I´ll have to fine tailor them to have a good fit), I decided to test a bit more on carburation.

This time I wanted to see how the bike would react to very low air input.
Intention is, having good control of main jet changes
Unfortunatly I only had the chance to make 2 small runs.
Setup this time with: AIR - #110 before ~ 8500 rpm, #60 after.
1st. run  - MJ #270 - very rich  - very hard to pass the 8500rpm area.
2nd. run - MJ #240 - still a bit rich on top - but now quite smooth on transition low/high RPM
This test has however, showed that main jet change has much bigger impact, and actually can be felt very good (while with big air correction, it is not the case).
It also seems that a cause for the bike to be "chocking" a bit at about 8500rpm seems to be the solenoide closing. Less air difference between close/open solenoid seems to help quite a bit.
So far... so good. Kind of was hoping for this scenario, because this now seems to go in the direction of fixed air jet... but small - less then #100. I have #80s comming, and a spare set I can bore to suit, #60s and #50s I already have... but not expecting to have to go so low... however, a smaller main jet also seems to be helping the 8500rpm area, meaning that in that area (as strange as it may seem) a smaller MJ, helps more then a larger airjet.
We´ll see how it goes. Major prob here... time.

Plugchop - 2 consecutive WOT runs 0-6th(11000rpm) - MJ #240 / AIR #110 - 8500rpm - #60 - max. EGT - 628*C
Lots of light to take pic. Color is actually darker... but, plug color, same in both sides ;)


Title: Re: 3MA trackbike project
Post by: casal-fan on May 30, 2015, 09:42:44 PM
Not testing engine anymore.
It´s running quite OK.

Edd. Experienced exactly the same prob. as you did/do with bike not reacting to throttle after a loooong WOT run, and hard on the brakes. It feels exactly as it run out of fuel. Not while at WOT, but after the hard braking, and trying to get it going Again. In my case, hard braking form 6th pinned to 10-5 km/h to turn around and go Again. It would not go, same feeling as when one forgets to open the fuel.
I tryed the same run, but this time timing gear changes so that the engine stays at high rpm, and giving it a good blip to keep rpm high while breaking. Better, much better.
I thought, maybe, under hard braking, and closed throttle, the pilot gets out of fuel supply because of the Gs that mess up fuel level.

I did not test this, but, I would like to test opening the choke, while hard braking, and see what happens. If the pilot is running out of juice because of the Gs, then choke would provide fuel to the engine, and this theori could be proven, or busted. But taking one hand of the bars to open the choke at WOT, fult tilt, might just be behond my bravery/stupidity limits ;D

So.
Final(ish) - (nothing is final ;D) setup is:

FAJ - #100
MJ - #240 (230 is a no go for me, 250-260 maybe a bit better, but I don´t have them. 270, and the bike gets very fat at 8500rpm
pilot #20 / ½out - almost doesn´t idle... Who cares, response is good like this.
stock needle all Down, stock needle jet.
stock PJ

Full throttle curve +2* (I did test with 0 curve -3* with FAJ - not as good as full throttle, lost acceleration as well as overrev, basically everywhere.

23 liters of fuel, used during the testing process, 0,75 liter oil, the thing is thursty as hell.
Ahh, by the way, don´t think I´ve mentioned it.
Been use this app while testing:
http://www.racechrono.com/

It seems to be quite accurate. I mean, what I felt as a loss in acceleration f.eks, showed longer time from from speed x-y for instance. Top speeds also seem to be accurate. Speedo reads about 10km/h more at high speeds, then GPS does.
I haven´t figured out how to download the data yet, but here are some numbers of the last run I did.

60-100 km/h - 1.5sec. / 50m
60-160         -  7.8sec / 270m
Title: Re: 3MA trackbike project
Post by: jools on May 30, 2015, 10:35:02 PM
Rui

as always a good read.

Do you think pushing the pilot jet up to 22.5 might help this pick up problem?
Title: Re: 3MA trackbike project
Post by: casal-fan on May 31, 2015, 12:17:42 PM
Rui

as always a good read.

Do you think pushing the pilot jet up to 22.5 might help this pick up problem?

Hi Jools.
I don´t know.

When I have the chance to take a look at the carbs, I will.
I came to think of this because of 2 Things.

1- Some years back I used to commute to Work by train. Once there was a defect window, the doble glassed type for insolation purposes, where water got in between the 2 layers of glass.
Imagine a this window, 1.5m long by 1m high, "filled" with Water to about 30cm to its total height.
When the train decelerated, (and this was a commuter train, nowhere near the Gs pulled by braking hard on a track bike), the level of the Water created a very steep slope, steeper then I would have imagine. Like the lowest edge was on the middle of the glasses length.
2- A few times, riding on the street on my RZ with normal carb config. on the back of the cylinders, a hard braking stop, and stay stopped, at a traffic light f.eks... and the engine would go out... like overrich out.
On the 3MA with it´s carb. config. this situation gets reversed - lean instead of rich. But, if this is the case, then maybe this is a major problem in design wich not easily can be fixed. Or... maybe easy anyway. I commented this with a mate at the workshop yesterday, and he had a very clever, simple solution... don´t break ;D

If you look at Juergens, very interesting research with his datalogger. You´ll see that even just by shiffting gears, closing throttle a bit, and mixture goes lean as hell. Now imagine this, and add the the situation described above... and maybe this is the recepe, for a crankcase filled with nothing then air after a long,  hard braking period.

I belive Edd can make a contribution her, with all the experience he has about the 3MA.
If the probs on his bike are worst, while picking up Again, after a long run braking, with shut throttle, this would somehow give this idea, some meaning.

Another thing is reeds.
It is generally accepted that a thinner reed will Work good at low rpms, while a thicker reed will be advantageous at higher RPMs.
Since I have (what I belive anyway) a setup somehow on the stiff side, it may be that I am in the situation where, the Little flow, my reeds let into the cases with shut throttle... might just be air flow, because of the pilots no having fuel to suck.

In the future, I´ll be working with this 2 Things in mind:

Frits Overmars writes this about the cagiva500 race bike:
"On a reed-valve engine the reeds are opened by the suction from the exhaust pipe. When you close the throttle, the energy flow to the exhaust stops, and thus the suction stops.
When you open the throttle again, nothing happens because the exhaust suction is absent; the reeds stay closed and there is nothing in the cylinder to combust. So the rider opens the throttle a bit more, and a bit more, and a bit... and then there is enough mixture in the cylinder to start combustion again. But now the throttle is wide open: Whamm, high-sider
!"

Wobbly on reeds configuration:
Use the softest carbons you can.
 Make a " rev plate " from the old reed 0.5mm material ie a strip say 6mm wide, this sits on top of the carbon under the screws.
 Then take the original thin fibre reeds, cut them to 1/2 length then cut them to make 3 pointed hats,these are backups that sit on top of the 0.5mm spacer.
 Next take the old radius plate and cut it to 1/3 its original length,this sits on top of the backups with the screws going thru all 4 elements.
 Best reed setup known to man.


The way I see it, this reeds "formula" helps in both hemispheres of the RPM scale, the softness opens the door to the cases even with minimal pressure differences, and then the back up reeds Work by effectively mimiking reducing the reeds length, increasing its natural frequency for good, high RPM performance. I wish I had seen this before I made my reeds.

It´s all good, just a hobby anyway.

Cheers
Rui
Title: Re: 3MA trackbike project
Post by: EEKNOWS on May 31, 2015, 01:39:05 PM
The lean spike isn't a lean spike at all that is misfires when the throttle is opened again. Reads lean as a O2 sensor just reads oxygen, no combustion excess oxygen appears in the gas. 
Title: Re: 3MA trackbike project
Post by: jools on June 01, 2015, 02:37:27 AM
So some form of baffle in the float bowl might go some way to counteract this or use a higher fuel level.

the other possibilty, and I'm not sure it would work, would be to drill a small hole in the pilot jet tube on the front side that the fuel rushes to under braking. This might provide an option where the surging fuel will be pushed into the pilot jet tube and give something to suck in until the level stabilises ?
Title: Re: 3MA trackbike project
Post by: Edd on June 01, 2015, 10:52:49 AM
Hi Rui

Very interesting. I have stated that I think it is my PV causing my dilema. Well your theory holds water and I know its sounds weird giving the pv the fault. I had my problem changing up usually into 5th it hesitated, and going into corners after the main straight and they are LH and RH corners but heavy braking is required. I also noticed not blipping the throttle helped significantly to reduce the time spend waiting for the mixture to come right.

At Phakisa I will run 4th 10000 rpm close the throttle open it and nothing I initially went 1/8th and waited for the mixture to come right and went again. Then I got tired of this and closed it and opened it fully and held it there to see what breaks ;D. The rpm went down to 8500 every time and then she fired back into life. My pv map was set 70 percent at 8500 rpm. Ant thats why I went that route I also changed the map and it just completely changed the bikes caracter I was unable to get through 7000 rpm way to rich. By the way I used the 3xv 00 map ;D.

My conclusion now is that if the exhaust port is way open suction is at a minimum and as soon as it closes the pressure diffrence is created and we have suction? By closing the throttle after a 4th gear pull you have significant forces going forward and when closing it shut the bike will decelerate causing the carb fuel level to move and pilots are out of the fuel sucking air.?

Edd
Title: Re: 3MA trackbike project
Post by: casal-fan on June 05, 2015, 10:24:37 PM
Hi Edd. I don´t know if the pilot gets out of fuel to suck... but facts are, the pilot jet sits about 35mm higher then the main jet. I recon with the correct float height, maybe it´s submersed 10mm tops when bike is static... so it is plausible that it could be sucking just air when decelerating.
What I did was I bored the pilots about 3mm Deep, 2 mm diameter hole and press fitted one of those tubes you get with aerosols, (my case brake cleaner) so that the pilot gets it´s fuel from the same low point as the main. I had one of those tubes submersed for 3 days in fuel, and its properties did not change.
The bike starts and revs fine on the stand.

Not doing more dynamic testing, now it´s time to get the last details ready...

Title: Re: 3MA trackbike project
Post by: maccas on June 05, 2015, 10:26:42 PM
Great idea!!

Hope it sorts it!

Dan
Title: Re: 3MA trackbike project
Post by: jools on June 06, 2015, 08:27:48 AM
simple solution, marvellous !

keenly waiting to see if there is any change

BTW - have you noticed the small plastic pilot tube extensions that the std 3XV carbs have......???
Title: Re: 3MA trackbike project
Post by: casal-fan on June 06, 2015, 11:08:16 AM
simple solution, marvellous !

keenly waiting to see if there is any change

BTW - have you noticed the small plastic pilot tube extensions that the std 3XV carbs have......???

Hi Jools.
3XV was a long time ago for me... but now you mention it, it kind of rings a bell.
The thing that I don´t know, is how large or how small the hole in the feeder tube needs to be, so it Works optimal.
Too large a diameter and maybe sucktion from the carb venturi won´t be strong enough to bring fuel up to the jet, too small a diameter. and then maybe it is the tube that becomes the meetering device instead of the jet.
If you have a 3XV plastic insert to the pilot jet at hand. Could you be bothered to check the diameter of the orifice that brings fuel to the pilot jet???

My setup idles fine, and responds to trottle blipping fine too, with #20 pilots and about 0.5mm hole in the feeder tube, but that is in a static situation where the fuel level is high. Dynamic situation could be different.

If this Works, I´ll considering changing my name to MacGyver ;D

Dan, do you think your 3D apparatus could make a neat insert?
Title: Re: 3MA trackbike project
Post by: maccas on June 06, 2015, 12:45:31 PM
I could try Rui, it's quite small though so resolution/accuracy could be tricky.

But defo could try it. Got a set of 3ma carbs with me too so i can fit them to make sure they work. If you tell me how long you want the dipper tubes and the hole diameter il get cracking

Dan
Title: Re: 3MA trackbike project
Post by: Jim Lyon on June 06, 2015, 11:18:15 PM
<SNIPPED>
Besides that it has the cylinders turn the wrong way arround (or maybe its the right way arround some would say),..


 If he was still alive, I think Walter Kaaden ( he designed the exhaust for the V.1 & from that learned enough about gas resonance to create expansion chambers ! ) would say they are the right way round! - Do a search on google for Walter Kaaden , when he was the race boss for MZ.
Title: Re: 3MA trackbike project
Post by: jools on June 07, 2015, 05:09:21 AM
I found one in an old bits box.

(http://i48.photobucket.com/albums/f202/Jools58/Pilot%20Nozzle_zpsri5mmzw3.jpg) (http://s48.photobucket.com/user/Jools58/media/Pilot%20Nozzle_zpsri5mmzw3.jpg.html)

The nozzle thingy is an odd shape with a flat edge. the hole is 3mm for its entire length

14mm length that is split goes inside the crab body tube. The projection into the float chamber has a chamfer at the bottom end, is 7mm diameter, 12mm long on the flat side and 11mm long on the opposite side
Title: Re: 3MA trackbike project
Post by: Louis on June 07, 2015, 12:44:58 PM
Just start to read/see your progress I missed, your extension tube looks very interesting.

It could be possible, the float height is dropping a bit on higher rpm and/or a long straight.
Closed throttle the only way the fuel can go is that route.

I'll be interested in your results
Title: Re: 3MA trackbike project
Post by: casal-fan on June 07, 2015, 09:17:09 PM
Louis, I tested just 3 or 4 times Down the road with hard braking... no symptoms of fuel starvation anymore, but nothing conclusiv because I wasn´t up to real speed.

Jools, thank for the info. Apreciate it ;)

Anyways... today, I gave the front braking system a Little overhaul, sanded pads, cleaned discs, etc.
Took the bike to my test area, and prepared or brake in the discs to the pads.
Also finnished my rattlecan paint job. I´m glad I don´t do painting for a living ;D
Missing the Marlboro decals, didn´t get them yet... but a couple of spy fotos anyway ;D

Title: Re: 3MA trackbike project
Post by: jools on June 08, 2015, 11:09:18 PM
Looks very nice

And, concerning another thread on here, I would not click the "like" button on principle............. ;D ;D ;D
Title: Re: 3MA trackbike project
Post by: Edd on June 09, 2015, 05:16:18 AM
Hi

Bike looks very sharp. I will also start some testing on the carbs soon. Want to test the tube theory.

Edd
Title: Re: 3MA trackbike project
Post by: jools on June 10, 2015, 02:20:12 AM
As I have the 3XV carbs on mine I'm wondering if those plastic pilot tube extensions will fit........

Remember the RH carb of the 3XV would have a similar issue as its forward facing, maybe they fitted them as a pair to save confusion. It could also explain the subtle differences between the two carb float bowls......????
Title: Re: 3MA trackbike project
Post by: casal-fan on June 10, 2015, 10:19:16 PM
Jools, I realised yesterday that I must have a set of 3XV carbs... somewhere. I´ll look into that, maybe NeXT week. For now, I´ll keep the lowbudget solution and see how it goes.

Edd, glad to hear you have not entirely given up on the 3MA. Imo. it is plausible that some kind of aid to feel fuel to the pilots from lower in the carb will help the problem.

After Work tomorrow, I´m of to Sweden. Friday and saturday - tracktime ;D
The 3MA will be measured against KR, 3XV, RGV, RS, and Honda RS... looking forward to it.

Cheers
Rui
Title: Re: 3MA trackbike project
Post by: jools on June 10, 2015, 10:49:12 PM
Have fun Rui

keep it upright  ;)
Title: Re: 3MA trackbike project
Post by: maccas on June 10, 2015, 10:58:01 PM
Good luck Rui!

Dan
Title: Re: 3MA trackbike project
Post by: Need4speed on June 11, 2015, 04:47:51 AM
have a nice trip
Title: Re: 3MA trackbike project
Post by: Edd on June 11, 2015, 08:39:49 AM
Hi Rui

Enjoy :D Had a look at the TZ carbs gfrom the 3ak and they have a plastic disc around the main jet. Has anybody have an idea what the purpose is of this disc?

Edd
Title: Re: 3MA trackbike project
Post by: casal-fan on June 15, 2015, 06:29:36 PM
Had a look at the TZ carbs gfrom the 3ak and they have a plastic disc around the main jet. Has anybody have an idea what the purpose is of this disc?

Edd

Edd, isn´t that just a feature on some TM carbs?
I have a set of 34s, they have the same ring, just in brass. I would imagine it acts as a stabilizer, so that the main always has fuel to suck from???

Well, guys.
The 3MA did not last long ;D 4 passes of 15 minutes, and then it gave up.
All 4 reeds shattered, not good.
Started slowly, I knew that the bike would show it´s real state on the track. A couple of scalded monkey runs up and down the street, show you nothing.
Felt lean on top after a couple of runs down the straight.
Jetted fatter - too fat, but then I had established an interval that would work good with my mainjet/airjet combo.
3rd time out, jetted ok on mains, still a bit rich it felt, it started hesitating a lot on the gas. I came in to check if a jet was blocked or something. One pilot jet tube was blocked.
By now, practice/qualifying was over, and still the 3MA managed a good enough time to qualify for the "slow" race.

4th outing, did not feel good, and got worst, lower then 9000 rpm was a no - no, and throttle response was very very vague.
By 4th of 5th lap, I stoped to see if I could see something obvious that could be causing this. Nothing to see... but then, bike would not start again.
Not start, first thoughts - plugs. Changed plugs, no start, plugs out again, dry as a desert.  :-\ Check fuel height good... check flow to carbs good... so, it could only be reeds... and it was.
A dns on the 1st race. But valuable info to work with... and many good pointers into the direction I need to work with the bike.
Still, 2nd time out, very rich, it was trashing a KR1, and running higher top speeds then a Martin piped, well setup 3XV, with only 5 gears to work with. Gearing was too tall.

Still had one day left, so I jumped in my reserve bike, I had taken my mito 125 ;D
Had never tryed this one on a track, so I jetted 2 sizes up, and here we go ;D
VERY, VERY funny bike ;D
I was getting trashed big time on the straight, especially on acceleration, top speed was 170 speedometer (very optmistic I´m sure :)) I was also suffering a lot on a long, snake like part of the track where acceleration is very important. And the worst, tyres. They were absolutly refusing to warm up.
After some sessions trying to figure it out, I ended up with VERY low pressures (tyres would take more then 3laps to warm, and by the end of the session they were melting) took a closer look, 8year old BT016 - ha ha, that´s why ;D
I changed my trajectories to maintain good corner speed (this caused problems because then I would meet the bigger bikes in the middel of the bends at lower speed then me >:( and sometimes they would slow me down... but in the end, I just rode for fun, tyres did not allow more, but what a wonderfull thing this chassis would be if it maintained its caracteristics, but with 50-60 HP.
Still, just missed qualification by 0.8seconds ;D

In the end it was good. I didn´t crash, and I didn´t destroy any engines ;D

A pic of the reeds, and another of the melted BT016 on the mito (they really kept my heart rate high in 5-6 ocasions ;D)
Title: Re: 3MA trackbike project
Post by: Louis on June 15, 2015, 08:33:19 PM
Quote
Well, guys.
The 3MA did not last long ;D 4 passes of 15 minutes, and then it gave up.

Well for a 3MA one hour off ''blasting around'' is not that bad ;)
Have hade quicker engine failures ::)

But how did it feels compared with other twostrokers?
Most guys have pumped a lot off money in there bikes and will have at least 60 till 70 HP.

Did you managed to accelerate a few times with them? (Can you hold up)
Title: Re: 3MA trackbike project
Post by: maccas on June 15, 2015, 09:25:09 PM
Are the openings on the reed block too wide Rui? Combined with too thin reeds?

Maybe try 3ma 3,4,5 reed blocks instead?

Dan
Title: Re: 3MA trackbike project
Post by: Need4speed on June 15, 2015, 09:33:40 PM
Quote
Are the openings on the reed block too wide Rui? Combined with too thin reeds?
I use the green Polini 0,35mm with no problem - but not in one piece...suggest that you made "fingers" this will take of the stress and the function improve.
 
Title: Re: 3MA trackbike project
Post by: maccas on June 15, 2015, 09:54:14 PM
I think Rui cut out one of the ribs on each side of the cage so the reed is spanning more than twice as far as it normally would. Can't remember now though!

Dan
Title: Re: 3MA trackbike project
Post by: Need4speed on June 16, 2015, 12:07:49 AM
Quote
I think Rui cut out one of the ribs on each side of the cage so the reed is spanning more than twice as far as it normally would.
Yes he did..
and it is always exciting to challenge the Yamaha engineers constructions - it is a fantastiks hobby we have - some times we are like the bumblebee that do not know it can not fly - but do it anyway :)
Title: Re: 3MA trackbike project
Post by: Edd on June 16, 2015, 07:45:40 AM
Hi Rui

In my book that is a good days work on a 3ma ;) Well done. Glad to hear she pulled strongly, once jetting is sorted she will make you a happy man ;D

Edd
Title: Re: 3MA trackbike project
Post by: casal-fan on June 16, 2015, 09:36:46 PM
Hi Edd.
I look at it exactly as you describe it. Little time, but precious feed back.

Need4speed and Dan, well spotted. I cutted 2 of the ribs. The 3 ribbed 3MA cages and reeds, are exactly the same dimensions as the the mito Evo1.
I also cut 2 ribs on the mito, and it´s working fine. Difference is the petals on the mito are custom made, laser cut, premium carbon specific for reeds. On the 3ma, cheap ebay stuff cutted with scissors ;D
They could not take the distance between the support  area that was given. Some of the edges of the reed blade, bent through the reed rubber seat, and inside the reeds cage. This gives pretty much a good picture of the forces involved in reeds action.
My plan now, is to put the std. reed cage in, fine tune the bike, and in the future get me some premium reeds stuff I can work with, but they are xpensive.
Need4speed, the reeds on the mito are "fingered" ;D, maybe that is better.

Louis. I have too, tchernobilised engines in much less then an hour.
I think this one was also close, but I started seeing and feeling some "strange symptoms" and took some of the advance out just a few days before I went to the track;D
I had troubles with jetting, but have now established a good main that works with the 100 air jet.
Lower rpm, middle throttle is still a problem, but I can not say why... maybe the reeds are to blame here as well.
I need to take a very good look at VAJ system, and see if it can be made to work in my favor. (I think it can)
The engine needs massive leaning, especially at middle throttle, middle rpm.
Ignition curve I think could work good, with TPS connected and +2/3 degrees.
We´ll see how it goes.

If someone has a 2 ribbed reeds cages laying around, I would buy them.

Cheers
Rui
Title: Re: 3MA trackbike project
Post by: Edd on June 17, 2015, 08:18:55 AM
Hi Rui

One question airbox or not? I wanted to run without, but after removing bottom half of the fairings and finding half of the Phakisa landscape and three quaters of Dunlop factory in the fairing decided to stick to bottom half of the airbox.

Edd
Title: Re: 3MA trackbike project
Post by: jools on June 17, 2015, 11:06:04 PM
Edd

you would need to construct some form of deflector plate mechanism with gauze at the openings

Look on the bright side - the sand will keep the pistons clean  ;D
Title: Re: 3MA trackbike project
Post by: casal-fan on June 20, 2015, 10:27:25 PM
Hi Edd.

I' m with airbox. Actually with the snorlels as well, but with the ends (the part that houses the rings) cutted of.
Mostly because this bike is not a full out tuning study. Enginewise I am being very carefull, trying to maintain and use as much of the stock components as possible.
As a rule of thumb, to squeeze the last ponies out of a 2stroke, a lot of special parts and Money and testing and time is involved. And frequency for changing parts for fresh ones goes sky high. (see my racing reeds, they lasted less then one hour ;D)
My 3MA is supposed to become (at some point) a reliable, fun trackday weapon. Not going for any records with it.

And, on with the research.
For some time ago, I did some testing on VAJ system. Already then I realised an interisting thing. The charts showned by Yamaha did not make sense, BUT they would make sense if by some mistake, my TPS was working backwards. Cut a long story short... it WAS working backwards ;D
Back then I took reference of some RPM numbers when the solenoids were closing or opening, and I made a chart that ilustrates how VAJ system Works. (Pretty much like the Yamaha chart, but with RPM numbers)... to the best of my judgement anyway, +- 500 rpm I 'd say.

The track also gave valuable input. These 2 "revelations" combined, will hopefully help to achieve a good setup.
Will have to get my thoughts together, and lay out a testing plan. Thoughts go in the direction of plug TPS back on, this time working as it should, some more advance via pick-up to about 12-14* 10750 rpm, and massive air correction at lower RPM ranges while keeping full throttle-high revs at about #100 air correction, which Works good on my engine AND gives good feedback when changing jets, i.e - can actually notice a jet change.
Such a setup seems to meet a lot of the requirerments I felt needed while testing... or might as well be a mess, we´ll see how it goes...

Title: Re: 3MA trackbike project
Post by: paul8899 on June 21, 2015, 01:58:06 AM
Interesting reading about the VAJ system. After altering mine it's a lot better to ride, it's not 100% but I think it could be with someone who knew what they were doing :)

When I was making sure I had the solenoids fitted in the correct hole I twisted the throttle ( without the engine running ) and I could see them switching on and off depending on throttle position.   

After riding mine I've noticed that if I have the bike running at about 4000rpm if I wind the throttle slowly the bike picks up well but when I whack the throttle full open it chokes up, I put this down to being used to cv carbs instead of slides.

I'm not 100% sure but it could be that if the throttle is wide open at 4000rpm that instead of having all 3 air jets open it's actually got the top end air jets opened. I'm thinking that the TPS could have more control over the VAJ solenoids than the rpm, it would explain why when the throttle is rolled back (so that it matches the TPS / VAJ map) it clears itself.

I'm thinking of unplugging the TPS so that the VAJ is only controlled by the rpm rather than the throttle position.

The downside is that I could be running with the airjets in fully lean mode which wouldn't be too good at full throttle  ?:-|

Does anyone know if the airjet system works without the TPS connected ?

Title: Re: 3MA trackbike project
Post by: Louis on June 21, 2015, 09:32:51 AM
Quote
For some time ago, I did some testing on VAJ system. Already then I realised an interisting thing. The charts showned by Yamaha did not make sense, BUT they would make sense if by some mistake, my TPS was working backwards. Cut a long story short... it WAS working backwards ;D
Yes, sorry my mistake :-[ I do give my apologies.
That such (small) mistake could have that big influence, my relief is that it not bow up your engine.
Have change it :)

Title: Re: 3MA trackbike project
Post by: Louis on June 21, 2015, 09:57:41 AM
Quote
The downside is that I could be running with the airjets in fully lean mode which wouldn't be too good at full throttle  ?:-|
Its a typical 3MA problem you are trying to solve. :)

One thing you can try is remove your TPS sensor from your carbs and put it (manually) on the 1/4 - 1/2 position.
Then mound a larger airjet in solenoid 3 (the one that is opening till 4000rpm) a smaller one in the 2 as it is opening till+/-8500rpm

You will be leaning your bike max till 4000rpm then it leans a bid less till 8500rpm and after 8500rpm you have one airjet in controle ;)


To compensate the ignition curve (witch is lower now) you have to ad a +3 three degrees to the pickup.
(with your cnc skills you probably can make something real nice 8) )
Title: Re: 3MA trackbike project
Post by: Warwick on June 21, 2015, 12:30:58 PM
Some really interesting work going on here fellas 8).

I know the 3MA3/4/5 have different sized oe airjets to the 3MA1s, but I thought all the 3MA1s were the same. I seem to recall that the the air jets in my 3MA1 VAJ block were 130 (1 - central), 50 (2), and 160 (3)?

Am I reading your stuff wrong, or do you guys have different jets in your blocks? ??? 
Title: Re: 3MA trackbike project
Post by: Edd on June 21, 2015, 04:39:44 PM
Hi Warwick

They did two diffrent 3ma1's. The 00 model and 01 model they had diffrent carb and vaj set ups.

Edd
Title: Re: 3MA trackbike project
Post by: Warwick on June 21, 2015, 06:45:55 PM
I didn't know the VAJ jets differed between the 00 and 01 CDI bikes. Just checked the 3MA1 manual and it gives the 130, 50, 160 combination, and the CDI number of 3MA-00, so that leaves me even further confused?

It's not crucial of course, but I'm just a little puzzled because, as mentioned, I'd assumed the first bikes with the 32mm carbs all had the same VAJ settings from the factory. What have you other guys got?

Just another 3MA carburation mystery I guess? :)   
Title: Re: 3MA trackbike project
Post by: casal-fan on June 21, 2015, 08:08:18 PM
Warwick. As std. my VAJ blok had the same jets in as yours. I hyjacked other jet sizes from 2 3XV Blocks I had laying around, some others I filled with tin solder and bored out to a specific size, and now I found some industrial ones with M4 thread, at 0.25 Pound a piece, so I´ll have the oprtunity to test a good range of open/closed combinations with different sizes. Main obstacle is time...
Or one could just plug some other needles in there and get on with it... but that would be cheating ;D

God to see you plug in this saga. Your 3MA is probably one of the best fine tuned out there, and all input is most welcome ;D
Title: Re: 3MA trackbike project
Post by: Warwick on June 22, 2015, 10:26:15 AM
Ah, thanks for confirming Rui. I think Loius also has different numbers too? Not sure if his were the stock jets or if he's changed them too?

My own 3MA has been out of commission for 3 years or more - since it last melted piston on the track... Martin talked me into giving it another chance over the winter, so we rebuilt the motor and he has been doing quite a bit of work on re-commissioning the chassis etc. We've only done a little road testing since the rebuild, but it is slowly getting there. We've gone back to using the airbox for the time being, but I'm not sure yet whether to revert to the VAJ system or use a fixed air jet. More testing of different set-ups needed. As it's only going to be a track bike the bottom end carburation doen't need to be perfect, so It will probably run a fixed air jet in the end. 

I'm too busy/lazy to run project threads I'm afraid, but once we have a track-safe set-up I'll post up some details in another thread. Martin is doing a trackday this coming weekend in fact, and he may take it along with him to give it a bit of a shakedown run. I half expect it will come back with molten piston smeared up one or both bores... :D.     
Title: Re: 3MA trackbike project
Post by: Edd on June 23, 2015, 08:58:30 AM
Hi Guys

Attached the std sair jet sizes for diffrent models. What I will do is translate it never realised it was in Netherlands.

Edd
Title: Re: 3MA trackbike project
Post by: casal-fan on June 28, 2015, 04:48:24 PM
Hi Edd.
Have you by any chance measured airjets, and can confirm/or not that the sizes stamped correspond to mm/100?
I only have equipment to measure 2 of the sizes I have, and it seems to be the case. my 130 seems to be 1.3mm in diameter, and 160-1.6mm in diameter.
Reason for asking is because, as it is air, not fuel they are meetering, the main point in changing them might be the size of the cross area. If it is so, then the numbers on the jets can be quite misinformative. F.exe. 2X #80 jets, offer about the same area as one #100 jet...

And a little update.
I managed to score a set of 3petaled cages from ebay, and will be working with those ones instead of my spare 4petaled.
Also plugging TPS back on again, to regain control of the air solenoids, but this time with a bunch of airjet sizes to try on.
Following advise of a fellow member I also booked some more tracktime at the same track where I got my first impressions on the 3MA. Hoping to get hold of a fast setup/reliable.
Title: Re: 3MA trackbike project
Post by: Edd on June 29, 2015, 05:41:42 AM
Hi Rui

I read in a post recently the size doesnt correspond with the number. They also posted a conversion chart. I didnt copy the dam thing should have. If you measured it and it correspond I must have tead incorrectly. Will see if I can find it again.

Edd
Title: Re: 3MA trackbike project
Post by: casal-fan on July 25, 2015, 10:03:00 PM
Hi Rui

I read in a post recently the size doesnt correspond with the number. They also posted a conversion chart. I didnt copy the dam thing should have. If you measured it and it correspond I must have tead incorrectly. Will see if I can find it again.

Edd

Hi Edd. If you find it Again, please post it. It would be usefull.

Anyway... I finally got some time to go to the workshop and mend the 3MA.
New 3 petal Cages from Japan, clened them, inspected them. They looked great! First tryed to get them inside my spacer... nope, they are wider then the 4petal design >:(  No spacer then I thought...
But the rubbers and stuffer on the later 3MA designs is also different >:( and I didn´t buy those >:(
So... alternatives were the 4petal design - wich I really don´t fancy, angles everywhere in those 3 ribs supporting the petals. In my idea, they must be quite restrictive to flow.
Or I could give the homemade reeds another go... this time with a better support area.

I choose the first alternative, and will see what can be done later... no time to speculate now, the bike is already  booked for 4 trackdays in august.

Some pics later... I also got the Marlboro decals it was missing. I think it´s a pretty bike.
Title: Re: 3MA trackbike project
Post by: Louis on July 26, 2015, 10:46:49 AM
You pointing out something I can test. :)

Have both sets.
Dynoing them both on one bike 4 petals vs 3petals with the combining carb rubbers

Could be interesting to see what the differences are:
4 petals smaller mass easier to bent could gain in the lower rpm.
3 petals bigger mass stiffer so would help in the higher rpm

Just a guess, will see.

How does the bike run? do you still use the 0 curve with shortened pipes? (still sorry about that)
Title: Re: 3MA trackbike project
Post by: casal-fan on July 26, 2015, 05:42:21 PM
At the workshop rigt now. Impossible to adjust my tps to the correct values. Maybe the tps is defekt. Louis. Have you measured 3ma-1 tps? Samme values as later models?
Title: Re: 3MA trackbike project
Post by: Louis on July 26, 2015, 10:31:29 PM
Quote
Have you measured 3ma-1 tps? Samme values as later models?
Yes, I have used different TPS sensor's all values where the same.
Also can't see a different part number for them throughout the years.

Quote
Impossible to adjust my tps to the correct values
That is a bid strange, you can turn it 360 degrees.
Are you perhaps in a aria where it normally does not come?

Do you have a tps sensor from a other bike?, wont be that different I think.
You can use that one.
Title: Re: 3MA trackbike project
Post by: casal-fan on July 26, 2015, 10:50:31 PM
Jeh, just remembered that I also checked part numbers in the past. they are all the same, yes.
I had noticed that something was not right with it in the past, but I did not investigate further because I wanted to run fixed ignition curve.

I have a 3xv one... will see if it can be fitted...
Thanks Louis.

Started the bike today, sounds good ;D
Title: Re: 3MA trackbike project
Post by: casal-fan on July 31, 2015, 10:38:44 PM
Since hability to get it to run 100% may simply not be there ;D (It´s close though... very close)
My TPS is acting stupid on me, so I´m still at a fixed ignition curve. This time the full throttle curve +2degrees.
Much smoother transition on the 8500rpm area, very smooth.
Quite snatchy on throttle pickup from closed... will have to see into that one, Bigger pilots could fix it maybe, but as luck would have it, amongst something like 25 pilot jets in the jets box, I didn´t have the ones I wanted.
I decided to take an easy task today. Cleaning it, and sticking some decals to it.

Title: Re: 3MA trackbike project
Post by: Louis on July 31, 2015, 11:06:22 PM
Looking good.

Quote
My TPS is acting stupid on me, so I´m still at a fixed ignition curve. This time the full throttle curve +2degrees.
That alone gained me about 1HP extra, on stock pipes :)

Now with your shortened pipes (peeking at around the 10800mark) the two degrees added, moves the 14 degrees right where you wanted it.
Good be a good one
Title: Re: 3MA trackbike project
Post by: paul8899 on August 01, 2015, 12:09:41 AM
I do like how that looks , I like that a lot  :D
Title: Re: 3MA trackbike project
Post by: casal-fan on August 02, 2015, 10:54:40 AM
Thanks Guys.
I´m rather happy how it turned out.

Looking good.

Quote
My TPS is acting stupid on me, so I´m still at a fixed ignition curve. This time the full throttle curve +2degrees.
That alone gained me about 1HP extra, on stock pipes :)

Now with your shortened pipes (peeking at around the 10800mark) the two degrees added, moves the 14 degrees right where you wanted it.
Good be a good one

Hi Louis.
Yes, that is the idea :D
Also, it seems like the VAJ opening sequences with the full throttle curve, makes for a smoother engine. Maybe I lost some punch in the 8500-9500 area, but the smoothness more then compensates for that.
I will try and adress the rather snatchy transition from closed throttle to maintainence throttle today.
Did a Little test yesterday with a slightly higher idle. It responded well... so maybe a smaller pilot jet would clean that up...
I managed to find #30 and #15 pilots, hopefully will test them today.
Title: Re: 3MA trackbike project
Post by: casal-fan on August 04, 2015, 01:47:54 AM
Still Work to do... Still think it´s not pulling clean in the 10-12000 area.
Took a vid. to help me try and figure it out.
5th and 6th maybe loading up with too much fuel???

https://www.youtube.com/watch?v=1VizNyjboXc
Title: Re: 3MA trackbike project
Post by: Louis on August 04, 2015, 12:50:29 PM
Remember it is a 250 ;D
Think it is running quit well.
In 5th and 6th most power is used, it goes slowly from there
Title: Re: 3MA trackbike project
Post by: Need4speed on August 04, 2015, 01:34:20 PM
Nice work - :)
Consider to make a vid of acceleration from 4.000 rmp to max in third gear... and the same i fourth gear - this will give you a more clear picture of the engine real performance for the track you go to..
What are you  sprocket size front/rear?





Title: Re: 3MA trackbike project
Post by: Louis on August 04, 2015, 08:09:27 PM
Watched you vid again, its running very good.

If I see how your speed goes up, and how it takes off.
Have a close setup compared with you, (shortened pipes) but I doubt if I could hold up :o

Same question here ;D

what sprocket size front/rear?
And how much do you weight?
Title: Re: 3MA trackbike project
Post by: maccas on August 04, 2015, 08:35:12 PM
Has your rev counter been calibrated Rui? 12k will be about 11300 real i'd guess if not.

It does sound a bit flat to me in 5th and 6th. It's definitely not lean is it?

Dan
Title: Re: 3MA trackbike project
Post by: casal-fan on August 05, 2015, 09:38:17 AM
Dan, it´s quite tricky...
No dyno, makes it very difficult to understand for me.
There are a lot of Things I try and look at. EGT, plugs, feel of the bike, how it behaves on different throttle openings, etc etc.
I´ll take it very easy and try to read the sign when I am at the track Again.
I´d also say the engine is loading up on rich mixture running at high revs, maintained WOT... but I´m not a gas analiser... so I´m not sure ;D I can try with a bigger airjet, and go from there.
Rev counter is not calibrated, and I´m also taking the error margin into consideration.

I should have done what you advise to do Need4Speed. A run in a single high gear would have told me MUCH more... ahh well, you learn all the time.

Gearing is 14-42 (+1 theeth in the back - yes, I know, I´m cheating ;D). I run 15-43 last time at the track, but this gave problems - this gearing is going to Work better in some parts that were not so good with 15-43. I also have other gearing options.
Louis - I´m @ 80(ish)kg ;D

Of to Sweeden this afternoon - 4 days @ the track with 3 possible races in between. I hope the 3MA does not fail. ;D
Title: Re: 3MA trackbike project
Post by: Need4speed on August 05, 2015, 01:16:58 PM
Allov me to suggest 13/43 ... for the reason that it's a small track, no long straight, and as/because you have not so much tourge in your engine set up - you will need to keep the "keddel boiling" -
If 13/43 as example- the "hairpin" can be done in 2.nd and you will be better in Rpm for the next lefthander... but only a suggestion -and wishing you a good trip and haveing a lot of fun. :)
PS: 13T are the same as used at Kawasaki KXF 250
Title: Re: 3MA trackbike project
Post by: casal-fan on August 06, 2015, 04:58:04 PM
1 Day finished. Very good Day.
Had to do some adjustments. Ill post final setup later.
Edd. Hesitation on gas on my bike is-was too fat pilot.
I m runnig the 2 fastet times out of 5 250s. 1.12.2 and im probably the worst rider ????
Credit to the machine.
Thanks for gear sugestion n4speed. Bike works good shifting at 11500-12000. Breaking after straight im at 11000-11500 feels like max power so gearing is ok. I can take harnale in 2. Torq is MASSIVE.
Ill post some vids when i come home
Title: Re: 3MA trackbike project
Post by: Need4speed on August 06, 2015, 05:18:14 PM
what class ?
Title: Re: 3MA trackbike project
Post by: casal-fan on August 06, 2015, 06:34:27 PM
Red
Title: Re: 3MA trackbike project
Post by: Need4speed on August 07, 2015, 10:07:10 AM
You can follow Casal fan on live timing http://www.motorsport-events.se/racemonzenergy/# (http://www.motorsport-events.se/racemonzenergy/#)
He is running "RØD" (RED) class local time 9:15-9:30/10:15-10:30 and so on - Race from 13:40 depending om Q time...

Title: Re: 3MA trackbike project
Post by: casal-fan on August 07, 2015, 05:10:22 PM
Thanks n4speed.
Qalified 8 in My race, but messed up start big time. Bike dies on me. I think the very lean pilot circut is the cause, but richer the bike will not respond good to throttle input. Was one of the last on turn 1 but fought my way into 12.
Tomorrow i have to find out why the bike just lods so much when lauching. Any suggestion Are very very welcome.
I ll post a vid of the race later. Amongst othr situations, blasting past a martin77 piped 3xv ;D
Title: Re: 3MA trackbike project
Post by: Need4speed on August 07, 2015, 06:13:14 PM
You were 2.nd in your class today :)
Title: Re: 3MA trackbike project
Post by: Louis on August 07, 2015, 09:37:25 PM
Great to her the bike is holding well, and is competitive to. 8)

Quote
Tomorrow i have to find out why the bike just lods so much when lauching. Any suggestion Are very very welcome.
My guess about this:
Could be that the building up starts when you roll the last 100m to the starting line. Position off your bike on the grid, and the waiting on the go sine.

This all (think) you will do in the lower revs, and it starts to build up.

You could try the following:

Half way the warming up lap, try to back off a bid (still driving in the higher revs) let the rest take positions wile you are coming and to take your position quick. Ones standing, give between the low revs some good blips (revving it up) in order to keep the crankcases clean.

Don't know if it will works, the idea behind it is to prevent it from building up fuel

Let us know how it goes, let that 3MA sing 8)

Cheers
Title: Re: 3MA trackbike project
Post by: jools on August 09, 2015, 12:10:58 AM
WOT and slip the clutch........... ???
Title: Re: 3MA trackbike project
Post by: casal-fan on August 10, 2015, 12:30:20 PM
WOT and slip the clutch........... ???

Yeah Jools! That´s the spirit ;D... I tryed that as well, but didn´t Work.
I had a tip, but didn´t have the necessary tools to do it right. It was the bikes first time out, where it actually worked, so I had a lot of other Things to absorve. I´ll Work on the start later.

So... 4 days at the track. Its a handfull. Bike gave good inputs.
Suspension. Rear is OK(ish) I would like to make it even better though. Direction changes can feel a bit unstable on the rear. A rebound issue I think... lets see how it goes.
                  Front is to the bears. Not good, can not change direction with the speed I am able to, becomes very unstable. Full lean is   dangerous. very unstable. You can see that in the vids. Will have to sort that out.
Geometri is OK. I´d like a bit more weight in the front, but with the front suspension as it is now, it would be risky to stress it even more.
Engine. Well... if we forget the starts... it´s OK. I could lean it a just a tiny tad I supose. Sound is GLORIOUS ;D
As it is, it´s on passe with the other 250s (the full power ones as RS and RGV, and keeps up with a tyga piped RGV regard the extra weight of the 3MA. 3XV-00 no port Work, just carb tuning and pipes... no match as you can see on the video.
Throttle input is good, torq is good.

All in all, its an OK track bike, that can be improved on to become an awsome trackbike. If it didn´t weigh so much, and with suspension Work, it would be quite fast.

I improved my times gradually, and day3 I set my fastest time, just beaten by an RS250 (with a lady riding it :-[  ;D) I think I could have had her if the suspension worked better... had 2 Collin Edwards knee saves trying to push, not funny, and very Lucky.
As for results. I was running in class moto 4½, an open class for bikes until 450cc.
Out of 3 races, got a 3rd and a 2nd place. Beaten by 2 moto3 NSFs on the 2nd race, and for the last race, one of them had went home, so I took second ;D But... quite embaressing nevertheless, Tino, one of the moto3 pilot is 12 years old :-[

I only have vids. of the 2nd practice/qualify on day1, and the first race on day2. Didn´t went very good, and I was being quite carefull, the following races went a bit better.
A mate took a vid. of it blating through the finish line, looking forward to hear it.
On the last day, 2 of my mates rode it, I only did race and 2 qualifying sessions. This gave me the chance to hear the bike myself. I almost pissed my pants laughing ;D

Practice:
https://youtu.be/Riakd4tTO04

Race:
https://youtu.be/4Kf8dICwoSs
Title: Re: 3MA trackbike project
Post by: Warwick on August 10, 2015, 12:47:12 PM
Nice work Rui! 8)
Title: Re: 3MA trackbike project
Post by: Louis on August 10, 2015, 05:02:22 PM
Nicely done, you let here sing the whole race :)

Poor clutch at the start :o
It looks like its not your engine that dies, its your clutch that locks it self bringing your rpm to a hold (then it almost choke it self)

Considering the bike (and technique) is coming from 89 she performs well agents her younger competitors 8)

Title: Re: 3MA trackbike project
Post by: casal-fan on August 12, 2015, 09:31:47 PM
Thanks for the compliments Guys.

I´m looking very forward to sort the front suspension out, as well as the suddent loss of power on take offs (I already have a couple of ideas to sort that one out).
It was a bit frustrating not being able to brake harder, or go faster on the bends because of the unstable front end... When I first found out this was not working properly, I was afraid of loosing the bike.

Louis, the clutch Locks, yes. But the reason the clutch Locks is because of the suddent power loss, that cuts the revs and the clutch engages. I would like to put it Down to me being a bad rider that can not keep revs up... but that is not the case. The engine Looses power. The start on the vid is actually the best of the 3 races. On the other races it was worst. The bike acted exactly the tipical problem of overrichness, brooooopppp, broooooop.

My considerations now have been that I can not lean the bike, as it is good as it is.
I could try a special setting, like a launch setting with all the solenoids powered up, or I could try the 0 curve Again with more advance, or, or... I´ll have to think about it... I have a hole long Winther to do it. No more racing this year, budget is used ;D
Title: Re: 3MA trackbike project
Post by: Louis on August 13, 2015, 10:54:32 AM
Quote
Louis, the clutch Locks, yes. But the reason the clutch Locks is because of the suddent power loss, that cuts the revs and the clutch engages
Ok, Well the engine sounds good when you revving here up just before start.
Don't understand why it suddenly drops the RPM like that, does not seems logical.

What ignition curve did you use?
Title: Re: 3MA trackbike project
Post by: casal-fan on August 13, 2015, 08:35:49 PM
Hi Louis.

This was my setup.
1 (wot) curve with +2*
#15 pilots - 2 turns out, and idle set to about 3000 rpm
stock needle and needle jet - leanest position
Right #230 / Left #240 main jets
air correction - sol.2 #50 / sol.3 #130 / always open #60
Air box - stock - but with the rings in the snorkels removed.
Pipes cutted 35mm
cylinders are "cleaned up", aux. exh. ports widened to the center (2mm wall between main and aux. exh. ports).

Plugs are NGK10. I did a plug chop - (trining video) and they came out, as clean as the Water from a glaciar in Greenland, but, the "ring" in the bottom of the ceramic was there (some say this is what Counts- I have no idea) I just took them out to look at them and assure something was not terribly wrong.
This Means (to me anyway) that I can not go leaner without risking engine damage.

When I am warmimg the engine, keeping it Bellow 8500rpm, all is good. Engine revs quickly, just as it should... for 4-5 minutes, after that I´m rich. Trying to give it more revs, the problem is WORST, because then it becomes really rich.

If I gave the bike 2 or 3 laps on ring its neck mode, and tryed to launch after that, I think the problem would not be there.
But, warm up lap, is not full ring, and the engine load up... it also loads up waiting for the lights, even if I blip it.
I can try some different Things, but it took me a year to get where I am, with acceptable performance... and to be honest, I have no idea what to try, I would have to Work along... I can not go leaner, and even if I tryed bigger mains Associated to bigger air correction, well, I´ve been there, and I did not like that main jet changes were very very hard to notice at all. Like it is now, a main jet change can be noticed quite easily, and that gives me some degree of security, or at least that´s what I tell myself ;D

If we assume that the problem is that the engine is loading, well, a solution could be to create a separate/independent electric Circuit that would power both solenoids open. I could switch this system ON while for exemple waiting for the lights, or ½way the warm up lap, and hope the engine would clean... But... this is only an idea, and it´s actually Agains track thumb rule of simplicity. But it would be cool to have a red button on the handle bar that said "launch" ;D
We´ll see...

It would be nice to hear if some of the other 3MAs that are used at the track have encountered this issue.





So, with this setup
Title: Re: 3MA trackbike project
Post by: Louis on August 13, 2015, 09:38:18 PM
Trying to think with you :)

You can try and see if your one way valves are working correct (or make your own)? This should help you to clear the crank cases better
Personally I have my doubts about this system, but Yamaha did not mound it if its not working.
Title: Re: 3MA trackbike project
Post by: paul8899 on August 13, 2015, 10:45:07 PM
Hi Louis.

This was my setup.
1 (wot) curve with +2*
#15 pilots - 2 turns out, and idle set to about 3000 rpm
stock needle and needle jet - leanest position
Right #230 / Left #240 main jets
air correction - sol.2 #50 / sol.3 #130 / always open #60
Air box - stock - but with the rings in the snorkels removed.
Pipes cutted 35mm
cylinders are "cleaned up", aux. exh. ports widened to the center (2mm wall between main and aux. exh. ports).

Plugs are NGK10. I did a plug chop - (trining video) and they came out, as clean as the Water from a glaciar in Greenland, but, the "ring" in the bottom of the ceramic was there (some say this is what Counts- I have no idea) I just took them out to look at them and assure something was not terribly wrong.
This Means (to me anyway) that I can not go leaner without risking engine damage.

When I am warmimg the engine, keeping it Bellow 8500rpm, all is good. Engine revs quickly, just as it should... for 4-5 minutes, after that I´m rich. Trying to give it more revs, the problem is WORST, because then it becomes really rich.

If I gave the bike 2 or 3 laps on ring its neck mode, and tryed to launch after that, I think the problem would not be there.
But, warm up lap, is not full ring, and the engine load up... it also loads up waiting for the lights, even if I blip it.
I can try some different Things, but it took me a year to get where I am, with acceptable performance... and to be honest, I have no idea what to try, I would have to Work along... I can not go leaner, and even if I tryed bigger mains Associated to bigger air correction, well, I´ve been there, and I did not like that main jet changes were very very hard to notice at all. Like it is now, a main jet change can be noticed quite easily, and that gives me some degree of security, or at least that´s what I tell myself ;D

If we assume that the problem is that the engine is loading, well, a solution could be to create a separate/independent electric Circuit that would power both solenoids open. I could switch this system ON while for exemple waiting for the lights, or ½way the warm up lap, and hope the engine would clean... But... this is only an idea, and it´s actually Agains track thumb rule of simplicity. But it would be cool to have a red button on the handle bar that said "launch" ;D
We´ll see...

It would be nice to hear if some of the other 3MAs that are used at the track have encountered this issue.

So, with this setup


I found that when mine chokes up and is struggling to rev I use a tiny amount of throttle it clears itself and I can then go back to normal use.

It could be that you are giving the bike too much throttle at low revs so instead of using the correct air jets the vaj is going into full throttle mode and choking the engine.

When I fitted my airjets I worked out which one opened at which throttle position by twisting the throttle ( with the engine not running ) and fitted them to the corresponding air jets.

If the vaj works the same when the engine is running then if you go straight to full throttle from tickover then the vaj is going into to full throttle mode and choking the engine.

The launch button is a good idea as I think that would cure the take off problems, just have to make it so when you release the button it goes back to normal mode ;)



Title: Re: 3MA trackbike project
Post by: Louis on August 14, 2015, 12:53:41 PM
Perhaps this could help you, just read out the airjet map :)
http://www.tzr3ma.com/3ma-01-cdi-solenoid-map.html

Beware that this is a 3MA-01 CDI the 3MA-00 CDI could have stored a different map
(the 01cdi is already different compared with the manual 00cdi)

The 0 curve does look promising ;)
Title: Re: 3MA trackbike project
Post by: casal-fan on August 18, 2015, 12:18:12 PM
Perhaps this could help you, just read out the airjet map :)
http://www.tzr3ma.com/3ma-01-cdi-solenoid-map.html

Beware that this is a 3MA-01 CDI the 3MA-00 CDI could have stored a different map
(the 01cdi is already different compared with the manual 00cdi)

The 0 curve does look promising ;)

Hi Louis. Again, you blow the competition away with your fenomenal investigation work.
Only if the 00CDI also could be investigated by someone, just to make sure ;D

These bikes were raced (or people tryed to race them with little or no sucess) here in Denmark. I wish I had access to the people that did it, and talk to them about what problems, and solutions they found.

I will for sure also keep developing this bike, and trying diferent setups, to see if I can get ever better results.
The 0 curve seems to have good potential, yes.
I´m think 100-120 in the middle and lower numbers operated by the solenoids could be interesting to test.

But, no more for this year, but next year I´ll see if I can start the season in your country. The event I sometimes attend in Holland is a more relaxed one just for fun.
Here in DK, there is always very busy. Jumping from side to side on a bike all day long. After a practice pass, you just have time to put on the warmers, take your suit out, catch your breath, and just when you nearly have it all together .. it´s time to go out again.
I used to have a lot of spare time at the track, when I was blowing engines or crashing ;D... so I guess there´s some development there already ;D

I´m looking forward to do more work on the 3MA, but by now... there are other not so exciting things to focus on ;D
Title: Re: 3MA trackbike project
Post by: Louis on August 18, 2015, 08:43:00 PM
I'm trying to help out, if my info helps others that is already Great. :)
I focus my self only on THE 3ma, so tests/developments/experiments Will only help for Those who ride that small part of THE Yamaha line.

Currently on à small holiday in Germany 8) typing this on my mobile phone is not Handy
WhEn I'm Back hopefully have Some new info for you

Cheers
Title: Re: 3MA trackbike project
Post by: jools on August 18, 2015, 10:45:18 PM
You are both doing a great service to the 3ma owners worldwide, I certainly find it invaluable to learn from your postings - even if I can't resist trying my own thing occassionally  ;D
Title: Re: 3MA trackbike project
Post by: Edd on August 20, 2015, 01:37:55 PM
Hi Guys

Sorry for butting in without reading all the posts. Have you tried to open the power valve at 1rpm to 3000 rpm. I have similar issues when pulling away. I am testing this theory next.

Eddie
Title: Re: 3MA trackbike project
Post by: casal-fan on August 23, 2015, 07:49:48 PM
Hi Edd.

3XV is like that, isn´t it.
I fail to see how having them open at such low rpm would help... but then again, I fail to see many things... ;D
Looking forward to hear about your research on that.

Edd, you mentioned you haven´t read all the posts in this thread.
I wrote some posts ago about how I managed to "mask" the hesitation on throttle opening response. Smaller pilots, and higher idle. This helped... a lot, but still not perfect.
Don´t think this was the solution to the problem. The origin of the problem might, and I´m quite sure it is still there, but this was the "patch" I managed to find.
Also, after longer(ish) periods of medium throttle, high rpm, the engine does not respond so good to blipping in correlation with raising engine rpm for smooth downshifts. This is a problem. Even with idle throttle set quite high, wich also eliminates engine brake, this engine brake effect is still noticable, and can mess up cornering start because the rear wheel judderes. On my bike, maybe suspension setup also is to blaim, but downshift with a good crisp blip of the throttle helps a lot, and on the 3MA sounds sooooooo good ;D
Title: Re: 3MA trackbike project
Post by: casal-fan on September 22, 2015, 11:50:32 PM
Drove to the workshop to look at some reed cages.
Spent ½hour to find them, measured them... and then I forgot to take the paper with the measurements with me ;D
Anyway...
This is based on cagiva mito reeds.
Boltspacing is the same in width (horizontal), but quite a bit less height (vertically).
The reason I´ve been looking at this, is that the 3MA reeds have a bit of an odd design, wich perhaps makes flow through the upper reed quite limited.
If a common design reedcage could be used, this would perhaps help the 3MA breed better???
The mito reeds (and perhaps others as well as with seems to be common to quite a few 125 and 250 models) could be used combined with a triangular(ish) spacer to point the tip of the cage upwards. The smaller height of the cage would allow this.
Mito intake rubbers are readilly availabel in many sizes wich would be practical if fitting the 3MA carbs.

Now, Louis testing has shown exellent results with the use of spacers.
Was this because of the increased crankcase volume? Or the reeds being placed further apart from the crankshaft, giving the incoming mixture not such a hard time filling the cranckcases and opening boost at the same time? - No idea ;D
But such a configuration with common reeds angled upwards would perhaps make the upper reeds flow better, while also opening the boost port. At the samme time the carb would perhaps not have to be pushed so much towards the wheel, as well as the carb mouth would have a lower position ergo more space in between carb and front wheel.

Just something I´ve been thinking about... it would involve some costs for sure, and in the end it would be just an experiment wich result could be either good or bad...
It would be interesting to try though... perhaps in combination with some drehmel work in the intake part of the engine block like Louis has done on his projectbike3 and looks very cool.
Something like this:
Title: Re: 3MA trackbike project
Post by: Louis on September 23, 2015, 10:11:54 PM
Quote
Was this because of the increased crankcase volume? Or the reeds being placed further apart from the crankshaft, giving the incoming mixture not such a hard time filling the cranckcases and opening boost at the same time?

That will be very difficult to say.

The 20mm spacer compared with the 12mm spacer was less, so on that point I would say to big crank case volume.
(as the boosterport where on both relative open)

Perhaps a a-symmetrical reedblock is an option to.
Just from pictures, looks like a Kr1-s has a nice shape (Lower reed stoppers pointing nicely towards the top, upper reedstopers relative flat)

Ore a other idea might be to rotate a (touch smaller) reedblock 180 degrees, so you have a NSR250 setup :)
Thought about that, could be a nice one (In combination with a spacer to make it all fit)
Title: Re: 3MA trackbike project
Post by: casal-fan on September 25, 2015, 09:47:46 PM
Interesting Louis.
Would really like to try this... but at the time (or for next season) don´t think I´ll have the chance as I already have other projects in the drawing board... maybe at a later stage.

Something else I came to think of, just the other day is this.
A LOT of 2 stroke machines have the upper reed covering the aux. transfer port. RD350, 2MA, RGV, etc etc etc...
It would be very unwise to assume all of these manufactors made this by accident. This has been on my mind.
Last week, it suddently occoured to me that if the pipe action creates a suction effect in the cylinder, that is transfered to the crankcase via the transfers ports, then there will be a time where the upper reed petal will be influenced directly by this "underpressure" right above it, and an "overpressure" below it, thus encoraging it to open, and stay open.
It could be that perhaps, maybe, who knows,  this is the reason why the reedsblok "covers" the port.
Title: Re: 3MA trackbike project
Post by: Jim Lyon on October 17, 2015, 12:08:25 AM
<SNIPPED>

Just for the record all other motorcycles cylinders are the wrong way around >:D Only the 3ma is correct

Edd

  If he heard that, Walter Kaaden ( race chief of MZ back in the '6-s would roll over in his grave ! - He learned his trade designing exhaust pipes for V1 "doodle bugs" & from that, went on to invent expansion chambers ! )
Title: Re: 3MA trackbike project
Post by: casal-fan on October 21, 2015, 07:52:35 PM
A mate sendt me some pictures of my last venture at the track.
I was suspecting that I had some suspension problems or I knew I had suspension problems.
This picture kind of makes me thing that at least one issue is the suspension being too soft.
Sags also say that, but I didn´t suspect it was this bad.
This is a maintainence throttle curve. Just maintaince gas, no brakes.
Both shock and forks are VERY compressed in my opinion...

Also a picture from the little mito ;D What a fun machine that was... I sold it... I feel very stupid.


Title: Re: 3MA trackbike project
Post by: ybk on October 22, 2015, 10:24:38 AM
I'm no good with suspension but I'm very impressed by the lean angle you're getting there :o :D 8)
Title: Re: 3MA trackbike project
Post by: maccas on October 22, 2015, 11:45:01 AM
Yikes indeed that is soft Rui! If you had to hit the brakes for some reason at that point you'd be off as the bike reached the end of it's travel!

Have you had a look on the tuning works website to see what upgrades are available for rgv owners?

Dan
Title: Re: 3MA trackbike project
Post by: casal-fan on October 24, 2015, 10:43:56 AM
Ybk, thats the tyres fault. Pirelli supercorsas are very good imo. A bit challenging to setup properly I think.
Dan, jeeh... that picture doesn´t really look that good. Both rear and front look VERY compressed.
I already have an SP fork with 0.7 springs that needs to be reconditioned, and for the rear, I´ll go for R6 shock??? I think that is the one Edd uses.
The suzuki shock being taller, also messed up linkage geometri a lot.
Hope to start with suspension improvements some time after Christmas...
Title: Re: 3MA trackbike project
Post by: Need4speed on October 24, 2015, 12:25:34 PM
Only some thoughts....

https://youtu.be/C60S79ovu7I?t=62 (https://youtu.be/C60S79ovu7I?t=62)

Consider to watch this video- It starts were your photo are taken.
In a car perspective you have not laying angles but notice G power symbol in the bottom left corner. (The symbol could (maybe) be a guide to were your motorcycle suspension are at work)
I think it is only natural that the motorcycle is overloaded at the place since you both have been running slightly downhill followed by a raised curve to the left in which the centrifugal force is to "throw" you over the next hill where the front wheel drop the asphalt or at least become much "light"

I think it's worth considering the weight balance between front and rear, more than it is about the free space. correctly configured damper front and rear should not give you clearance problems, in my opinion. but it's only you who can decide  :)
Full video:
https://youtu.be/C60S79ovu7I (https://youtu.be/C60S79ovu7I)
Title: Re: 3MA trackbike project
Post by: casal-fan on October 25, 2015, 12:33:03 PM
You have a very good point n4s.
But... I have to do something, because I´m not comfortable with the suspension, and it is always in the back of my mind when riding the thing.
Again, good point on the g-forces on that curve, not exactly where the pic. was taken, but right before the track has a very nice angle at the riders favor where you can almost ride horizontaly ;D, so agree on the g-influence.
I have been looking for such pics for a long time... to see where suspension was at, and this pic. even with taking into account that the suspension on this curve is very loaded, perhaps, maybe it should not be so much loaded???

I made dogbones to set swingarm angle at 11*, and looking at the pic, it almost seems that the swingarm angle goes negative? Even if the shock spring is 3/4 pre-compressed.
On another hand, on the mito, it looks much better, even with std. suspension, the forks are not so compressed, and swingarm attitude also looks better.

There is a good chance that I´ll ruin more then I achive... but hey... at least it will be trying something else, and see how that goes ;D
My idea is the 0.7 kg.mm springs instead of the less then 0.6 in the front - monted on an sp fork with both rebound and compression control, and a CBR600rr 05-06 damper at 10(ish) kg.mm (after looking at some threads on this amazing forum), and another benefict would be the relative equal measurements of this shock when compared to the original 3MA shock - std. dog bones wich wont mess up linkage geometri that much?
Also have to remember that despite me being around the same age and height as Rossi... I like my flaeskesteg (pork) a lot ;D wich means that there might be a considerable difference in weight ;D

We´ll see how it goes...

Title: Re: 3MA trackbike project
Post by: Edd on October 26, 2015, 01:06:12 PM
Hi

In my opinion yamaha shock is easier to fit than the showa shock. They are exactly the same on handling side.

Edd
Title: Re: 3MA trackbike project
Post by: casal-fan on October 27, 2015, 10:28:48 PM
Edd, sorry if you have posted your change to R6 schock already, but can I ask what year R6 shock you were/are using, and in wich points you found it to be easyer to mount then the CBR600RR shock???
Title: Re: 3MA trackbike project
Post by: casal-fan on January 18, 2016, 10:28:21 PM
Long time since I wrote here.
Mainly been thinking of ways to try and improve carburation. Very difficult because there is not much info out there.
Have been studying the rgv race manual regarding jetting, since that might be the most extended piece of document regarding jetting of the TM carbs on a twin 250cc.
http://vinceracing.pagesperso-orange.fr/downloads/RGV250_hop_up_kit_manual.pdf

Have some ideas to try out as soon as the weather warms up a bit.
First of all, std. needles are gonna go out and I´ll try to find something leaner until at least 3/4 of throttle opening... see how that goes.
Another thought goes in the direction of big air correction, asssociated to small main jet, and up the powerjets to #60 - #70... but... we´ll see if there will be time to try all this.
Would also like to change the airbox to a different design... but think I might keep it as it is while I try some carb setups first... also for the sake of documenting the most I can without many mods at one time.

Suspension wise, have a fully adjustable set of forks on theyr way from Japan wich will be overhauled as well as spring rate adjustment , and the GSXR shock will go out west, in favor of a R6 unit - shorter providing more linear compression ratio as well as a bit stiffer.

As usual... lots of things to do, and experiments to try... and short time.
The 3MA is already booked for it´s first outing in 2016 - Assen TT circiut the 9th and 10th of april together with the YTCN Nederlands chaps, always lots of fun.
This was last year, one of the several 2stroke sessions:
https://www.youtube.com/watch?v=VO5Mv6GDBo8

Title: Re: 3MA trackbike project
Post by: maccas on January 18, 2016, 11:27:07 PM
I always thought that manual described the airjet function incorrectly. If you ran a large airjet and a small main jet, the fuelling in the midrange would be good but as the air speed increased the fuelling would go mega lean!

The only way to get acceptable mixture strength at the top end with a large air jet is to have a large main jet too. Which then causes excessive richness in the midrange! (this is ignoring powerjets and programmable stuff of course).

I always think about this useful image and description from John Robinson:

Dan
Title: Re: 3MA trackbike project
Post by: maccas on January 18, 2016, 11:30:42 PM
Sorry it's the wrong orientation! I'll try again

Dan
Title: Re: 3MA trackbike project
Post by: casal-fan on January 19, 2016, 12:10:39 AM
Hi Dan.
Exactly those 2 documents rgv manual and robinson have been buzzing on my head, and been thinking of something that would somehow conciliate both of them...
For some peace of mind... I stopped ;D and now look forward to some good times with the spanners and the jetsbox to actually try some ideas.
I am with you (and robinson) that correcting richness by opening air will gradually agravate with rpm increase to the point where the engine will become excessively lean, this is why I would like to install larger PJs working independent from the mainjet circuit... even if my trust to the powerjet system on the 3MA carb is at best... doubtful...
Guess time will say... my engine, jetting wise feels very good at lower then 1/2 throttle openings, perhaps alone a leaner needle with a long straight section and shallow tappers will work good? Have 3 or 4 pairs of those from 2.65 to 2.75 straight section...
There is also the pilot circuit and the deal braking non existent throttle respons problem after a closed throttle period... but that is another story... no pilot airjet on the 3MA carbs, air correcting only provided by idle mixture scrue???

We´ll see... looking forward for some jolly spanner time ;D
Title: Re: 3MA trackbike project
Post by: casal-fan on January 19, 2016, 12:18:54 AM
And, I think Robinsons example was with another type of nozzle then the one 3MA carbs use? No idea if that also can be relevant?
Title: Re: 3MA trackbike project
Post by: Warwick on January 19, 2016, 12:22:14 AM
As you'll doubtless find when you get yours up and running, Dan, the reverse motor design of the 3MA seems to mean that the 'right' overall jetting will still leave it running less than perfectly at lower loads...

I reckon the best chance of getting it something like reliably and dependably usable at all engine loads will be to use the VAJ system with a programmable ignition to allow you to use a big ol' air jet at lower loads to prevent it 'loading up' with unburned fuel when burbling about, then  transitioning to a much smaller airjet at the top to keep it from melting itself into oblivion when given the berries. Maybe using quite a bit of advance at lower loads will help too?

Certainly in my experiments, it works best at lower loads with a fair sized airjet. As noted though, you then need a pretty big main to keep it safe at the op end, and this in itself can cause issues lower down... It's a constant trade-off balancing act between main, airjet, Needle/needle jet and even the pilot air screw... Change one thing (or even if the weather changes...) you end up back in a cycle of changes trying to find the right balance again. Get it slightly wrong and it will shit itself...  :D.

If I had the energy and inclination I'd definitely be getting busy with experimenting with programming the VAJ system.  It must be about the only thing I haven't tried... :).   
Title: Re: 3MA trackbike project
Post by: casal-fan on February 03, 2016, 01:38:45 AM
If I had the energy and inclination I'd definitely be getting busy with experimenting with programming the VAJ system.  It must be about the only thing I haven't tried... :).

Nothing more exiting and grey mass developing then a challenging task Warwick ;D

Soon be putting the 3MA on the work bench and start preparing it for 2016 season.
Some ideas to try out, some of those I´m even reluctant to put out here, afraid of being discarted as a loony...
For now I would like to ask your opinion on an electric matter I´ve been thinking about.
It relates to a problem I found in 2015, launching the bike from start it bogs severely. There are 2 things I would like to try about this. One is to rump up ignition timing, the second is the installation of a switch to gain control over one solenoid on the VAJ system.
Gaining this control would also be interesting, to test the influence of the air correction system at several engine loads as well as rpm.
The system would work by feeding 12V to the solenoid by operating a switch of some kind. This would in theori allow me to open an air solenoid even when the ECU is telling it to shut down.
But... since my knowledge on electrics/electronics is pretty much unexistent, I´m asking youguys to take a look at the pic. I´m posting and give me your opinion if this thing will work.
I´m specially concerned about the possibility of the second 12V feed from the switch could somehow damage the ECU???
Thanks in advance.

Cheers
Rui
Title: Re: 3MA trackbike project
Post by: jools on February 03, 2016, 05:01:47 AM
I haven't examined the circuit diagram of the 3MA VAJ (yet) but if it is the same operationally as the 3XV then it will be switched on the negative side, which is opposite to what you show in your sketch. Most of the electrical systems controlled from the CDI switch on the negative side I believe. The Brown wires are switched positive feed from the ignition switch ie isolated when ignition switch is off. The coloured wires from the VAJ are the switching negative wires and earthing any of these, either by switch or through the CDI, will operate the corresponding solenoid.

So in this instance if you bypass the CDI wire with a switch to earth it should not have any damaging effect to the CDI.
Title: Re: 3MA trackbike project
Post by: Paul on February 03, 2016, 10:05:57 AM
You Could put an inline switch to "disarm" the aj
OR
The Cdi "earths" the circuit. It will have 12v permanently in the one wire and the other will go to ground when the cdi is programmed to.
Test which wire has 12v and take the other to your bars and make a switch that goes to earth. You can control it manually then.
Title: Re: 3MA trackbike project
Post by: maccas on February 03, 2016, 10:47:07 AM
Rui,

As Paul and Jools note it's a switched earth that opens the airjets.

The beige/pink wire going to the airjets is the live 12v, you want to earth the red/black or green/black to open either pair of airjets.

Use a handlebar mounted kill switch, will be ideal for the job as they usually earth to the handlebar as part of their design.

You could even use a handlebar mounted horn switch that way the airjet would only open when you are holding the button leaving no risk of leaving the airjet open as you race off the line!

Dan
Title: Re: 3MA trackbike project
Post by: casal-fan on February 03, 2016, 11:35:30 PM
Ok guys, thanks for the comments.
Off course the ECU eaths and disearths the several things... most work thay way, thanks a lot for clarifying that.
I´ve updated the pic I posted earlier

I was thinking of adapting a lever brakeligh switch to the clutch lever, and using the clutch levers clearence of 3 or 4 mm to operate the switch. Switch off if clutch lever not influenced, switch on only by pressing the lever a bit even if not influencing the clutch operation. As an added bonus... my hand is already at the clutch lever, if... ;D
But still don´t know, time will say.

Title: Re: 3MA trackbike project
Post by: Paul on February 03, 2016, 11:41:48 PM
Remember putting 12v in, i.e. Earthing it will switch it on OR close the AJ
So it must be permanently on and when you pull your lever you kill the 12v power and AJ will open
Title: Re: 3MA trackbike project
Post by: maccas on February 04, 2016, 09:01:09 AM
It's the other way around Paul. Airjets open when they are powered up. The electronic powerjets close when they are powered up.

Dan
Title: Re: 3MA trackbike project
Post by: casal-fan on February 04, 2016, 09:57:32 AM
According to my research, documented on this thread some pages ago, I also think that the VAJ solenoides on the 3MA are open when powered with 12V, and closed when not powered with 12V.
Will try to confirm this.

Thanks for the input Guys.
Title: Re: 3MA trackbike project
Post by: Paul on February 04, 2016, 08:06:06 PM
Could be. The idea is there. Test it and use it.
Title: Re: 3MA trackbike project
Post by: casal-fan on February 20, 2016, 02:54:23 PM
I got a set RGV SP forks from Japan, to fit the 3MA (already had an RGV front end setup) and started to rebuild them.
Not going good...
The rebound adjuster piece is well stuck, and me not exactly being the most clever or pacient man in the face of the earth managed to make a mess out of it :(
I had the piece soaked in anti seize, and warmed it to push the rebound adjuster out of the cluster for inspection and clean up, but its not going well at all...
I kind of feel a bit left down by myabeeplus here as well, as they only posted one pic of the stanctions... the one in good condition. The other one is badly pitted and it will take hours of precision work to get to working order.

Any input or ideas to help me drive the adjuster piece out of the cluster are welcome... I´m really crying here...
Title: Re: 3MA trackbike project
Post by: jools on February 21, 2016, 04:17:05 AM
Those brass adjusters are sh*te

I had some R6 type that one was completely mullered and they don't appear to be easily stripped down.
I ended up buying a complete set of forks (without the stanchions and cartridges) just to get a spare.
Title: Re: 3MA trackbike project
Post by: casal-fan on February 21, 2016, 10:51:09 AM
Those brass adjusters are sh*te

I had some R6 type that one was completely mullered and they don't appear to be easily stripped down.
I ended up buying a complete set of forks (without the stanchions and cartridges) just to get a spare.

Thanks Jools, I feel much better now :'(  ;D ;D ;D

No... joke aside.
Being kind of used to work on old bikes, one meets all kind of challanges. One thing I´ve learned is perserverance is the key word. Just keep choping at it and one will succeed for the most part of the times...
Well see how it goes, heat gun-releasing oil, heat gun-releasing oil... and I hope I eventually press it out...
Title: Re: 3MA trackbike project
Post by: casal-fan on February 25, 2016, 03:32:43 AM
Got the bas***d out.
Wasn`t easy though...
Will have to remake the top of the adjuster.
Heat, heat and more heat.
The other side came out quite easily in comparisson to this one.
Waiting for parts, will do a spring cut, then assembly.
R6 shock has arrived, I had it serviced by the shop I bought it from and is ready to go. New dog bones to go with it, as it is shorter then the GSXR shock (and shorter is a key word here)...
After a lot of considerations, I´m quite hopefull this new suspension setup will do good.
Title: Re: 3MA trackbike project
Post by: ybk on February 25, 2016, 08:36:55 AM
Well done! Very satisfying isn't it :) Was rebuilding my 3xv SP forks just now as well, interesting how the brass adjuster is quite different on the non adjuster end. The 3xv is concave instead of pointy like this one.
Title: Re: 3MA trackbike project
Post by: casal-fan on March 17, 2016, 11:56:26 PM
Long time since I wrote here...
2016 season is aproching very rapidly.
Bike is booked for 2 days at assen in holland, mainly to try out some new settings.

I did suspension work.
The soft gsxr shoch was changed for an R6 shock with an 8.5 kg.mm fitted wich was borrowed from the bigger sister, the R1.
Big thing with the R6 shock is that it is about the same length as the std. 3MA shock.
Forks were exchanged for første generation USD RGV SP forks.
I got these because they look much more like the yamaha forks, without the gold anodised wich I kind of don´t like anyway.
Forks setup... well, I gave suspension a lot of thought this winther. Even if I´ve tryed some things in the past, it really never got behond cutting some springs, try different oils as well as airgaps... wich is OK, but I wanted to lear a bit more this time, and it will be interesting to ride the bike with these ideas implemented.
For the forks I had 4 spring sets. 0.5 - 0.55 - 0.6 - 0.8
Went for the 0.6 instead of the original RGV 0.5. The 3MA is probably a bit heavier, as well as the weight distribution might be a bit more front biased.
A little twich is that the 0.6 springs I have are 25mm shorter, so I did a spacer of 20mm. Why only 20mm???
Well, here it goes. I think that I´ve traced some of the front end instability, special when changing direction rapidly as well as a bit up and down circuits to too much preload. This was maintly to keep forks from bottoming. But as a setback, the suspension would have no free sag when not stressed. This perhaps caused the front wheel to loose traction/contact with the asphalt more easily causing front end didturbance... just a thought.

The results.
Not conclusive as I finished very late today and had nobody to help me measure.
But I have just a bit 2-4mm of free sag at the back with about 25-30mm rider sag - with the 8.5 spring with the less preload possible - this is quite a good result - I was aiming and hoping for something like this. The short R6 shock I belive also gives a increasing shock rate, more then the GSXR shock.
Front is a bit more difficult without help, but the short spacer trick will do for the purpose of my experiment. The front sags about 18-20mm with no preload - and 26-30 with me sitting on the bike (not conclusive) - but these numbers are also in the ballpark of what I was aiming for - I was interested on good sag numbers using stiffer springs with little preload. The front also feels much more supported now.
I used 10W oil with 110mm airgap - I might take some oil out depending on how much travel I´m getting on harsh braking.
I am excited to setup sags with someone helping me, will report when I do.

Work continues now with new experimental engine setup, both ignition and carburation wise.

Pictures:
https://onedrive.live.com/redir?resid=5752D07CB385386F!5568&authkey=!AAoYiWnMq1e-AAE&ithint=folder%2c
Title: Re: 3MA trackbike project
Post by: maccas on March 18, 2016, 10:17:21 AM
Sounds good Rui!

The suspension linkage on the 3ma is completely different to the 3xv as on that i'm using a 132N/mm rear spring.

Have you got the racetech suspension bible? It's VERY handy and gives a great insight into set up!

Those sag numbers sound pretty good. On the rear of my bike the free sag is 0 and with me on board 34mm. Rear feels fantastic.

Front i'm working on!

Dan
Title: Re: 3MA trackbike project
Post by: casal-fan on March 18, 2016, 10:52:55 AM
Hej Dan.
No, I don´t have the racetech bible unfortunatly. Can it be downloaded for free ;D
A lot of costs with track time this year, need new tyres, new pads, already bought new tyre warmers... it adds up very quicly.

Dan, I´m also positiv about the numbers I´m getting, even if I haven´t checked them with the help of someone - meaning it is now quite inacurate. If something - I would like to see a bigger number between free and rider sag at the front. Free sag is good IMO - rider sag - too Little IMO, meaning the 0.6 springs are a touch too hard...
But, easter is comming - Family reunions with a lot of good food and cakes, so I´m not changing the spring just now ;D

Will get back after I have set the thing up.
Title: Re: 3MA trackbike project
Post by: casal-fan on March 18, 2016, 08:09:42 PM
Measured sags properly.

Rear:
R6 2007 rear shock with ~8.5 Kg/mm spring from R1
Preload at minimum
Dog bones - 137mm
Free sag - 0mm (simply rests at 0mm, the slightest input will show movement in the rear though - it´s not hard)
Rider sag at riding position - (75kg rider) -26mm

Front:
RGV SP 41mm USD forks
SV650 first generation linear rate 0.6 kg/mm springs with spacer - total length 5mm less then stock springs
Preload - 4 rings showing
Free sag - 20mm
Rider sag at riding position - 35mm


So, I guess a slightly softer spring in the front would theoretically make me happier. Rider sag is pretty much OK I guess, but would like to see a slightly lower free sag nr.
Made proper calculations from my notes - front rider sags are pretty much where I wanted them to be with the 0.6 Kg/mm spring.
All in all, I´m confident that this setup will help the bike not feeling like a boat, as it sometimes did last year.
Only testing will say.


Title: Re: 3MA trackbike project
Post by: Louis on March 18, 2016, 10:49:58 PM
Quote
not feeling like a boat
Like a what  ;D


Its looking great Rui  8)
Your chassis setup knowhow goes much further then mine.
I'm already happy when my 3MA lower it self when I'm sitting on it O:-)
Title: Re: 3MA trackbike project
Post by: casal-fan on March 19, 2016, 02:18:18 PM
Had a better look at my notes book - made a calculation mistake on front rider sag.
Numbers updated
Title: Re: 3MA trackbike project
Post by: casal-fan on March 25, 2016, 11:12:45 PM
A step forward toward having the bike ready for the 9th of April for a few sessions at the track.

Today I focused on carburation setup.
I wanted to try this for a long time. Different needles.
Since the carbs had to come out for cleaning, I thought it was a good time to do this. I found 6 sets of needles that might be worth considering, and compared them to the 3MA-00 needles.

The choice came upon  6BGY-71 instead of the 6FL-63.
Now, this needle is quite a bit fatter then the original wich will make carburation on the needle circuit leaner. Transition angles are smoother then std. needle.
We´ll see how that goes... I hope good, because having to change needles again will be a pain.
Also switched idle jets from #15 to #20.
Mains stay at #230-#240.
Air correction goes from #240 all open/#130 full throttle to #130 all open to #80 full throttle with the 0 curve instead of 100 curve before.

Tomorrow I buy some fresh 99 octane and will try to start the thing, and see how it feels with these changes.
Pics. tomorrow.
Cross fingers for me ;D
Title: Re: 3MA trackbike project
Post by: Need4speed on March 26, 2016, 09:17:39 AM
Quote
Cross fingers for me
will do  :)
Title: Re: 3MA trackbike project
Post by: casal-fan on March 26, 2016, 09:54:16 PM
A good afternoons testing.
Only one problem... I seem to be loosing more and more power as I try new setups ;D
Computer software seems to be out on easter holiday... so, no pics either on this post.

Now...
I tested the 0-curve with 1-2* less advance.
It seems my bike likes better the full throttle curve with +2 advance - going back to that.

Needle change - Not conclusive - but after some testing I think this needles opens good chances for elimination of ECU controled air correction.
I tryed some biiiig air correction at lower rpms - #300, and the thing was very clearly lean with all the solenoids open acounting for #150 of air correction. This possibly means that FAJ is now possible - not possible with the other needles.
Will test FAJ when I have the chance.

Full throttle high rpms with Right - #240 main #150 air and Lefr #230 - #150 is working OK, showing nice plugs. Right side might still be a bit lean though - will up to 245 main and see if it gets better.

Suspension feels good - might need bigger air gap on the forks.

All in all - nothing conclusive - just some good pointer on possible directions to follow.

Important question to Louis:
Louis, your findings on the VAJ system.
On your website, the nice chart you made, you call the solenoids 1 and 2.
Is that the equivalent of 2 and 3 marked on the vaj blok? Equivalence from your site being 1=2 and 2=3  ???
Title: Re: 3MA trackbike project
Post by: Louis on March 27, 2016, 06:36:34 PM
Quote
Important question to Louis:
Louis, your findings on the VAJ system.
On your website, the nice chart you made, you call the solenoids 1 and 2.
Is that the equivalent of 2 and 3 marked on the vaj blok? Equivalence from your site being 1=2 and 2=3  ???

I have measured it again (found a small mistake sorry, I'm just a amateur)
Have uploaded the new chart with only the 0 and 1 curve.
And with the explanation witch solenoid is witch in my chart
http://www.tzr3ma.com/3ma-01-cdi-solenoid-map.html

Looks like the 0 curve would be good to use (solenoid speaking)

I find it interesting to read that your bike likes the 1 curve with 2 degrees9 more) better then the 0 curve with 2 degrees (less)
It is hardly different, perhaps the controlled airjest makes it feel different
Title: Re: 3MA trackbike project
Post by: casal-fan on March 28, 2016, 09:32:08 PM
Yes Louis, it might very well be something to do with the way VAJ operates with the different curves, but it really feels like the bike is more "loose" with the 1 curve+2*, and yes, 1+2* and 0-2* is very much the same I had seen that one, and I also wondered.

Next testing, plan is to see how the bike reacts to FAJ with the new needles - I think good, but never know with the 3MA.
Also test with with VAJ with 1 curve and VAJ leanig the bike slightly at high rpms.
We´ll see how that works.

Cheers
Rui
Title: Re: 3MA trackbike project
Post by: casal-fan on April 01, 2016, 05:46:57 PM
Engine setup, quite good.
Been experimenting a bit...

Also setup suspension the best I could after a test ride, and hopefully suspension oil was a bit warm
Front:
Free sag - 22mm
Rider sag - 40mm

Rear:
Free sag - 2mm
Rider sag - 32mm

Going to start here.
The warmer oil, influenced sag numbers quite a bit.
I think the front might be a bit too hard... and maybe the rear a bit too soft.
Front has very little preload, and quite high oil level. Now, only the track can tell me more.
Rear is at minimum preload wich is what I aimed for. One notch preload brings rider sag to about 24mm wich might work better... maybe.
All in all, the goal was pretty much achived. Quite firm suspension at minimal preloads because of the increased spring rates, but still a lot of soft movement in the upper part of suspension travel.
Well see how it goes.

Cheers
Rui
Title: Re: 3MA trackbike project
Post by: casal-fan on April 09, 2016, 02:11:17 PM
Bike run very good for 5 laps :-X Then big end did not want to play no more :-X
Title: Re: 3MA trackbike project
Post by: maccas on April 09, 2016, 02:33:30 PM
Ah shit Rui that sucks! Hope the big end pin is salvageable...?

Dan
Title: Re: 3MA trackbike project
Post by: Need4speed on April 09, 2016, 03:00:43 PM
send me a PM when you get back - I have spareparts for repair..
Title: Re: 3MA trackbike project
Post by: casal-fan on April 14, 2016, 12:27:56 AM
Engine dissasembled... this is gonna be expensive :-[ :-[ :-[
Bit dissapointed... such a long drive to holland for about a dozen of laps.
The most of them on an RD350 powered RGV chassi I borrowed from a mate. They run good these contraptions...
Title: Re: 3MA trackbike project
Post by: casal-fan on April 22, 2016, 02:36:30 PM
Been looking for parts for rebuild... a lot of search, and found some interesting things that would create a miriad of parts that could add up for some interesting setups... but, since a member here, so kindly offered to help with OEM conrod and cranshaft parts, decided to take a more conventional route.

I found a good big end bearing, flat cage, silver coated, for the conrods - CR250 with 24mm crankpin - (pjme is now selling them)
Then piston... wanted a cast piston like OEM, so that excluded the wössners. Prox or mitaka have the hole above the pin, and while it is reported to work just fine, it just don´t feel right. So, the hunt for a suitable cast piston began.
Decided to go with an italian cast piston for an older model cagiva with nikasil bore.
The piston is from a company called GOL that has been in the bizz for almost 50 years, and was among others OEM for gilera.
Cast piston, no holes above the pin, very good reputation amongst the TZ250/350 guys, 1mm rings instead og the thicker 3MA OEM piston, shinny crown... looks OK.

Here is the tecnical sheet is someone is interessed.
http://www.pistonigol.com/public/stampa/Report500.pdf

Also include a good pic. of a GOL TZ350 piston, and this is theyr promotion video. I don´t like it... I love it ;D Old school has always been a fascination. An italien that had ½liter of wine for lunch instead of a taiwanese with a whith cloth covering his nose at the levers of a lathe... that´s style ;D
https://www.youtube.com/watch?feature=player_embedded&v=DOyk-0R9jDY

So, now awaiting delivery of parts, crankshaft is already at the crankshaft guy... hope to have it running again for the 10th of June, but... not holding my breath...



Title: Re: 3MA trackbike project
Post by: jools on April 23, 2016, 01:28:41 AM
What a great video

That's the first time I have seen how they make a cast piston.

No wonder manufacturers insist on a minimum qty order.

This is a video of the forged type manufacturer

https://www.youtube.com/watch?v=dVLrAce8lHE
Title: Re: 3MA trackbike project
Post by: casal-fan on June 06, 2016, 11:00:27 PM
Getting there...
Break-in planed for friday, at the track ^-^

Title: Re: 3MA trackbike project
Post by: Need4speed on June 09, 2016, 05:29:53 PM
ref 2nd gear difference  ;)
Title: Re: 3MA trackbike project
Post by: casal-fan on June 11, 2016, 08:55:30 AM
N4speed. That is quite What feels says it would be good ;)
Quick up date on my first Day of 3ma run in and testning.
It went good. Runned rich on purpose. Didn t blow a bit les power but win drive wich is good at this track. Suspension testning a lot. good base setting found wich is a major step.
Today testning continues.
Wich me luck  ;D
Cheers Rui
Title: Re: 3MA trackbike project
Post by: casal-fan on June 12, 2016, 11:43:46 AM
Update - day2

A very good day, I´m very happy.
One very last top-end jetting change after the bike had run about 1 hour and engine was decleared run-in and ready to be pushed. Very subtil change - only top end air correction went from #50 to #60 after 8500 rpm. On a note, while this was a subtil change, the plugs showed it.
Interesting is that the bike has perhaps a bit less top end power now, but gained massively in pull ability - 7000 rpm to 11.500rpm is just a build up of power, still overrev to 12.000rpm. I like this.
A very subtil change on shoch rebound as well (had a bit of help from a guy that used to work for hyperpro and had his camp right besides me and my mate).

There was a lot of traffic in my group, and with only 30 minutes qualifying I didn´t manage to get a clear lap, and ended 11 out of 31 in the C-race (for the slow guys ;D) This was OK, because I knew the bike could absolutly not launch from the line (this problem will be adressed in the future-think I have an idea why).
To cut it short... 11th at start to last on the first corner. This was not so bad, because I really got some training about overtaking ;D - Finished 14th but winner of the moto4½ class. The 400s and the other 250s managed to overtake.
This was possible because of a much more concentraded focus on smothness and keep corner speed as high as possible. This was also a bonus because with the improved corner speed, the engine now manages 3rd gear in a lot of places I used to run second gear. Of course a better scalled gearbox would be fantastic for this track still.
It was a very interesting experience overtaking so many people in the race, I learned a lot, it really puts all your capacities, both physic and mental on the highest level of awareness.
A friend took a a small video of one overtake. 2bikes in one go on the brakes, and then maintaining speed and momentum to get a good drive out of the corner.
Bad phonecamera video, the 3MA shows at 09 seconds, and then my friend follows it. Sounds good also ;D
https://www.youtube.com/watch?v=bq9vWGmG-E4

Now, the launch problem...
I need a TPS sensor I think I have established good settings for WOT and the uper rev. range with the TPS locked on the WOT settings. Plan now is to get tps fully functional, for me to take control of lower rev range as well. So if someone has a good spare 3MA TPS sensor laying around, I would like to buy it, mine seems to be not so good.
I have no idea where to find one besides here on the forum.

Some more pics.
My mates 3XV together with my 3MA
The moto4½ class podium with 3MA-3XV-VJ21
Title: Re: 3MA trackbike project
Post by: Eric_TZR_TDR on June 12, 2016, 01:13:31 PM
The sound makes up for the low res movie ! As long as you enjoyed the ride you won the race   ^-^
Title: Re: 3MA trackbike project
Post by: Paul on June 12, 2016, 01:26:38 PM
Superb review there.
Title: Re: 3MA trackbike project
Post by: Louis on June 13, 2016, 10:49:56 PM
Hello Rui,

Good to read that the 3MA stayed in one peace, and performed well at the same time ;D

Hope you find the launching problem.
As for a racer like you, you lose all the hard work what you did for qualification :-[

Will follow your findings with great interest :)
Title: Re: 3MA trackbike project
Post by: Toop on June 13, 2016, 11:56:53 PM
Thank you for the report, have fun  ;D
Title: Re: 3MA trackbike project
Post by: casal-fan on June 14, 2016, 12:41:55 AM
Thanks Louis.

By the way, the research I am doing is heavily based on your research, so there is hardly any credit for me...
What you research, and your suggestions seem obvious to me, so I mainly  just follow them.

For exemple.
Your research on TPS control of the VAJ system. This has a very important value for me.
I know my TPS sensor is not in 100% working order., but I can make it to work because you have measured what values correspond to what curve. I do not think there is another "modern era" 250 2stroke with so much info available.

At the track I spoke to a mechanic called Ivan Saaby. He works at a large yamaha dealer, but 2strokes are a passion for him. We spoke about the old days, and he told me that in the year of 1990 when there was 2 or 3 TZR 3MA racing here in Denmark, nobody could get them even near as fast as mine is now.
Besides the launch problem, my 3MA is a fast bike... but I am sure it would not be, if I did not have info on the air correction system f. exemple...

I would like to get a good TPS sensor, because I think this would open for a very large tuning window, but, your tip on the 0curve and how VAJ is functioning there, I think that maybe, perhaps is all that is necessary. Only that in my opinion the 0curve maybe, perhaps, possibly needs minus 3-4-5 degrees less advance...
I understand now that the launch problem is because of too rich mixture at low RPM. I run #20 pilot jets because #15 or #12.5 is very small, and can get clogged very easy, and destroy an engine :-[ (ask me why I know that... I have an oval conrod to show... ;D)
I am looking very forward to work on the 3MA again, and test it again with new settings based on the experience from the last 2 days at the track. I am confident... but also aware that the bike is a 3MA... nothing is granted ;D

And yes, it is irritating not to be able to pull of the line, would like to be fighting for a race podium place instead of a class podium, unless you name is Marc, this is impossible if you are last at the first corner ;D
https://www.youtube.com/watch?v=2R-Aq_4ejH0
It is hard to overtake... 3 seconds after this picture, I had overtaken 3 riders ;D, but a total of 15... is not easy on a 6lap race...
We´ll see what future brings...

Cheers, Rui

Title: Re: 3MA trackbike project
Post by: casal-fan on June 18, 2016, 12:01:42 AM
A few more action pics from day1 - engine break-in and bit more gas at the end of the day.
Title: Re: 3MA trackbike project
Post by: tzr-v4 on June 19, 2016, 12:03:57 PM
Great pictures.
I'll the little 2 strokes going around 4strokes in the corners  :))
Title: Re: 3MA trackbike project
Post by: casal-fan on June 22, 2016, 12:30:59 AM
Yeah... a couple of good days at the track.
Target of running the engine in without brealing it was achived. I always get so scared when engine is new/rebuilt, but this time it went good.

Started on development again.
The last 2 days allowed for precious testing as well, and some carb setting were some settings were deliberatly tryed so a better understanding of the engine could be gained. This also was quite enlightening.
For the next outing, the 0 curve, and the air correction setting it opens will be tryed. I hope to work with this and achive a good engine setup that is largely based on the current but also allows the bike to pull from a stand still situation, because right now all it does in such situations is to kill every living moskito in a 10km radius with all the smoke ;D.
Pics of ignition curve comparisson, full throttle+2* is blue - red and yellow are 0 throttle with -4* and -3*. VAJ settings as measured by Louis with 0 and full throttle openings.

For reference the last carb and ign. settings were:
Pilots #20 - 1 and 3/4 out on the scrues
Needle are - std. needle first clip with Q8
230-240 mains
#80+#50 air correction before 8-9000 rpm - #50 after
WOT curve with +2*

Next outing should be mid of August.
We`ll see how that goes.

Cheers
Rui
Title: Re: 3MA trackbike project
Post by: casal-fan on July 24, 2016, 09:08:56 PM
So...
Lets go back to the misterious "engine went on holiday, try again later" scenario that some of us found on our bikes when trying to accelerate out of a corner, after costing with shut throttle slide.
Don´t focus on the explanation, but could this be worth a shot to try?
It kind of makes sense... on my 3MA, this problem was almost solved by having the slides very open at closed throttle.
From Wobbly on Kiwibiker on why Honda RS125 pressure airbox kit specifies to make a 2mm hole on the top of the carb slide:
"When running a sealed airbox you have residual pressure inside this volume after backing off into a corner.
With higher pressure on the intake side of the slide, and virtually no flow into the engine you will get an excess of
fuel being picked up by the idle circuit.
And when getting back on the gas the engine is then suddenly partially flooded with overun fuel.
The hole in the slide equalizes the pressure on both sides and prevents the airbox pressure from all running under the cutaway and
into the idle circuit.
Helps quite a bit in stopping those highsides that hurt like hell. "


My calender doesn´t allow me to make this before the next outing.
Someone willing to try? Paul, Jools, Louis, N4S, others????
Title: Re: 3MA trackbike project
Post by: Paul on July 24, 2016, 10:20:00 PM
I found it was the speed I opened the throttle.
So I worked around it. Let it gurgle around corners with throttle cracked slightly.
I've sold the 3MA now. I only have the 2 V twins.
Title: Re: 3MA trackbike project
Post by: Need4speed on July 25, 2016, 04:43:09 AM
My focus would be here ;)
Title: Re: 3MA trackbike project
Post by: casal-fan on July 26, 2016, 02:56:10 PM
Wow Paul, never thought that one was gonna happen, hope you got what you espected for it. It was (is) the Charlize Theron of the 3MAs.
N4S, that one is on the "try" list.
Me using the spacer was kind of choosing between pest and colera. A lot of things point to that excess volume in the intake duct is a no go... but a crankshaft in front of the reeds is a no go as well???
Still, I am going to try and remove the spacers at some point.
Many thanks for the suggestion ;)
Title: Re: 3MA trackbike project
Post by: Need4speed on July 26, 2016, 10:25:27 PM
Quote
but a crankshaft in front of the reeds is a no go as well??
is it  ;)
Title: Re: 3MA trackbike project
Post by: casal-fan on August 14, 2016, 09:11:58 PM
Good point. My idea of letting more air in the carbs before 8000 didn t work.
Was at the track today.
Major tyre slip after 2 lap yellow flag at slow pace,  managed to hold on and survived the consequent high sider. Tyres Are done I think. They reached the change now mark ????
Problems with noise. See pic. It works. 2db reduction wich allowed me to run the bike with regular 94 DB measurements ;D
Bike run good.
Will post some more pics later.
Title: Re: 3MA trackbike project
Post by: casal-fan on August 28, 2016, 12:18:45 PM
Well... I guess the fotographer this last time at the track was not a 2stroke fun.
Only pics./mov. is a video taken of my race...
Took a look at it... and I´m not pleased... actually I am very dissapointed.
Qalification time says I should be fitting in the middle of the pack, but yet I just managed 3rd last :-[
Few reasons... the big one, is obvious... THE START.
I get out of the first corner last of the pack, 6 seconds behing the guy in front. >:( Something has to be done here... this start-get of the line problem, if not solved will make that I retire the 3MA from racing. It is also dangerous for me and the guys behind me.
Race lap times are also well down. Confidence after an highsider got to the bottom, confidence in the bike has to be reestablished.
Gearing - I desperatly need a higher 2nd. gear
Tyres - 6 y.o. (I´m even ashamed to admit this ::))
Suspension - Having difficulties here as well. Especially the front.

The positive sides.
The 3MA is consistently the fastest 2stroke out there (there aren´t many though-wich helps ;D)
A qalifying time 57th best out of a pack of about 150-160 ridders including the best national riders from Denmark, Sweden and Norway on top of the pops 1000 and 600cc. This on 27 y.o tecnology with down to 1/4 of the engine size ;D

Development continues...
Here is the video:
https://www.youtube.com/watch?v=IuFFwe0tX_Q


Title: Re: 3MA trackbike project
Post by: Need4speed on August 28, 2016, 12:53:01 PM
Quote
Something has to be done here...
remove the spacer in front of your carburettor and your are were you whant to be  ;)
Quote
I desperatly need a higher 2nd. gear
Told you  :D - maybe I can find a ekstra set if i look in my "tool box" PM if needed...
Nice ride anyway  :)
Title: Re: 3MA trackbike project
Post by: casal-fan on August 28, 2016, 08:35:19 PM
You have PM N4S ^-^

Just watched the vid a couple of times again...
From 1.31-1.39.
Think I might get one of those helmet comunicaton systems with the mic. placed by the exhaust so I can listen to the 3MA better ;D
What a sound ;D... and that is rich... way rich.
Title: Re: 3MA trackbike project
Post by: paul8899 on August 28, 2016, 10:59:14 PM
What problems are you having with the front suspension ?

Are you using the Rgv triples / yokes and if you are how do they compare dimensionally ( fork centre to stem centre ) to 3ma ones ?

It might be that the different fork offset is making the bike feel strange at the front, I know that changing the fork offset on my R1 makes a huge difference to how the front of the bike feels on the brakes and through corners.


Edit: I just had a quick google and found out that the rgv uses the same fork offset as a 3ma ( 35mm )



Title: Re: 3MA trackbike project
Post by: maccas on August 29, 2016, 09:36:24 PM
Rui,

Just watched the vid. Wow, that does sound amazing.

What symptoms are you struggling with off the line? Are the cases loading with unburnt fuel?

Maybe it's time to add a VAJ "start" button on the handlebars that you hold to clear it then let go of it as you start revving her up to go?

Dan
Title: Re: 3MA trackbike project
Post by: casal-fan on August 31, 2016, 04:24:08 PM
Dan.
Problem of the line is that the thing does not go...
When it finally gets going there comes really heavy smoke from the exhausts, so my guess is that it is rich.
I also made a Little test.
I was the last to go to the grid forming lap, and gave the bike a spanking, it cleared up. When I got to the grid i let the bike idle, just idle for one minute or so before taking of to the sighting lap. No go - very bad.
This could make me belive that the problem is the pilotjets??? Test, test and more test... is the only solution as I see it.

Paul, front suspension feels OK... except when there are irregularities like bumps of rugged asphalt. Then it feels too harsh. Many tunning possiblilities, so I´ll keep working on that as well.
Title: Re: 3MA trackbike project
Post by: paul8899 on August 31, 2016, 08:15:31 PM
That's good to know that it's possible to tune the harshness out, guess it will just take time.

Have you got the vaj system fitted to the bike or are you running the fixed air jet ?

If you are using the fixed air jet you already know what size air jet to run for the full throttle air jets and with a bit of messing around you can tune the bottom ( and mid-range ) with the vaj system.

With the vaj fitted you could have a button that opens all the air jets for take off which should allow speedy getaways
Title: Re: 3MA trackbike project
Post by: Paul on September 01, 2016, 09:09:55 AM
Sounds sweet Rui
When tuned they are prone to a little crank flooding on idle. Could be you dedicate one solenoid to idle to slow fuel entry down, Paul's idea is good.
They are fast bikes, Lightning acceleration
Title: Re: 3MA trackbike project
Post by: peterbike on September 01, 2016, 10:43:09 AM
Rui, re your front suspension problems have a look at this ;
http://www.ducatittandf1.com/viewtopic.php?f=24&t=11337
you can contact Glynn on his website,  sportsducatimotorcycles.com
Apparently work very well for RWU forks.   $570 kiwi dollars
Title: Re: 3MA trackbike project
Post by: casal-fan on September 01, 2016, 10:59:17 PM
Hi Peter.
I´m using VJ22 SP USD forks with a harder .6 spring.
Still well over 20 years tecnology, so there is a good chance the valve inserts would work better...
Thanks for the tip, apreciate it!


This is not fair.
The cool launch button opening big air from the VAJ was my idea in the first place  ;D ;D ;D ;D ;D ;D
No, joke aside, in the setup I run this time there was more air from the VAJ feeding the engine then the time before, with no apparent better results. On the other hand... idle setting has big impact. A high idle engine speed helps this "overfueling" a lot, both on take off and gas respons after a period with the gas shut.
It might be possible that the more opened slide at idle, provides the engine with more air to blend with fuel from the pilotjet making things better.
There are a couple of sugestions from members here I´m going to try out, but perhaps there is another ting to test, cutting the evil by the rooth :)
Pilotjet is already very small, but Louis might already have found a solution... (see pic. below)
We´ll see.
Track time budget is used for this season... the engine rebuild took a lot of that, but still hoping on taking the bike to a closed road along with the toolbox and make some experiments...

Cheers
Rui
Title: Re: 3MA trackbike project
Post by: casal-fan on February 17, 2017, 05:26:30 PM
So... it´s been a while something happened here.
Starting to prepare the bike for 22-23 April, 2 days at the track.

The keystone for my carburation experiences for 2017 has arrived.  Q-0 jet setters.
I asked Louis what he knew about them, he sent me some links, and then I google like crazy to try and find them in europe.
I ended up finding them in Germany from TW parts
http://tw-parts.com/index.php?inhalt=artikel_detail&ordnerArtikel=vergaser&seiteArtikel=mikuni_abstimmungsteile&menu_nr_offen=15&beschr_id=Mikuni-785-40003-XX&fahrzeug_id=156

Send Sebastian an e-mail if someone is interested... he is a very nice chap and helpfull.
The part number is Mikuni 785-40003-*-* the 2 digits missing being the size. Sebastian told me the only size that was not on stock was P-0

I´ll write a bit more about what I have in mind carburationwise for this year at a later stage. Right now its just damm cold in the garage.

Cheers
Rui

Title: Re: 3MA trackbike project
Post by: Warwick on February 17, 2017, 08:29:28 PM
Nice score! Good luck with those, Rui!
Title: Re: 3MA trackbike project
Post by: maccas on February 17, 2017, 10:02:34 PM
Great stuff  8)

Dan
Title: Re: 3MA trackbike project
Post by: loor on March 14, 2017, 06:21:38 AM
Hey Rui,

Mikuni Topham (www.topham.de) in Germany can supply the correct Part 610-Q? although it is not listed anywhere. Just drop them a E-Mail.
Price is 14,35€ / pc

Cheers, Lorenz
Title: Re: 3MA trackbike project
Post by: casal-fan on March 15, 2017, 01:05:57 PM
Hey Rui,

Mikuni Topham (www.topham.de) in Germany can supply the correct Part 610-Q? although it is not listed anywhere. Just drop them a E-Mail.
Price is 14,35€ / pc

Cheers, Lorenz

Hi Lorenz.
My guess is that if you know the part number, you can pretty much get the setters from any mikuni dealer.
Gonna try them soon. My hope is that these leaner setters will open the door to experiment with quite different VAJ setup in relation to what has been experimented before... but more on that latter...
Title: Re: 3MA trackbike project
Post by: casal-fan on April 20, 2017, 10:23:01 AM
Couple of hours during the last 3 days to get the 3MA ready for its first outing in 2017.
It will be Assen TT circuit, this coming weekend.
New tyres, after 2 sets of Pirelli supercorsas decided to try something new. Went for racetecs RR from metzler soft front and medium rear.
Since this track is a killer for bikes that are not correctly setup, decided not to change to the Q-0 setters , but maintain the Q-8s.
Also felt that experimenting was not quite done with the pair Q8s – air correction. During winther time I tried to make sense of what was going on jetting wise during the 2016 season, and I had a few tests to make.
These tests were based on having the TPS locked in the WOT curve +2* advance, and both solenoids operating.
I had realized for some time that there seemed to be a connection between the 3MA not being able to get on the gas after coasting into a bend – and richness, both at low throttle openings but ALSO longer WOT runs. This tells me that maybe there is a scenario of rich mixture at full, encountering the rich mixture at closed throttle – leading to over-over rich situation when trying to get on the gas again.
This pointer as well as testing different air corrections until and after 8500 rpm as well as find a good transition were the base for the testing.

The setup of the bike is now as follows:
100% throttle curve +2*
Pilots #20 – airs. 3.5 open
Needle circuit - Q-8 /all down (lean) 00 needle
Mains – #240-250
Air – 1-80 / sol2-50 / sol3-100

Only a very short test run with this last setup – but bike seemed to run perfect – well better then ever before at least.
Short rides are all but conclusive… but I´m interested on keeping working in this direction.
Will try to post some fotos this evening if I have time.

Any Dutchy feeling like saying hello. Assen TT circuit the 22 and 23 (this weekend).
Lots of interesting 2strokes to have a look at.
Title: Re: 3MA trackbike project
Post by: casal-fan on April 20, 2017, 10:39:31 PM
Final checks done.
Gazzzzzzz :))
Title: Re: 3MA trackbike project
Post by: jools on April 20, 2017, 11:49:24 PM
Hi Rui

looking forward to reading more, and thanks for posting up your settings.

I ordered several sets of needle jets from your contact Seb, thanks for the details

please remind me again -

1 Are you still using the airbox ??
2 what needles are you using ?

cheers

Jools

Title: Re: 3MA trackbike project
Post by: casal-fan on April 22, 2017, 02:30:40 PM
Little report.
Bike running ok. Improved topspeed a lot.
Cold. 8-10 degrees.
Title: Re: 3MA trackbike project
Post by: casal-fan on April 24, 2017, 02:44:16 PM
Made this little video of my last outing.
Temperatur was very low. 7 degrees C i think.
Reduced tyre pressures - big mistake. Bike got very twichy and unstable.
Costed me some off-road exploration :)) May not look like it, but going thru the gravel trap wiggling from side to side with the barrier comming closer and closer wasn´t fun at all...

All in all, very usefull track time.
Happy with the bike. New tyres, very cold weather, new circuit for the bike, and we got within 5seconds of the very fast IGK 250s with theyr top tuned apes 250.
https://www.youtube.com/watch?v=LvkgVX03j5M

Very interesting event. A hole world of 2 stroke machines. Frm 500 to 50cc
This video from a racing prepared FS1. At 16.10, my 3MA hunting a top notch TZ350.
https://www.youtube.com/watch?v=5P9xOx7h7uw

Title: Re: 3MA trackbike project
Post by: casal-fan on May 01, 2017, 09:19:57 PM

1 Are you still using the airbox ??
2 what needles are you using ?


Jools, sorry man, forgot about this one.

Still using the airbox, yes.
Needle is the one for 32mm first generation carbs. - all way down.
The snorkles are cut at the bend, and air filter is  5-7mm thick ventilation filter material.

About jetting... I did enrichen the hole thing by replacing the always open #80 by a #60.
100% throttle curve +2*
Pilots #20 – airs. 3.5 open
Needle circuit - Q-8 /all down (lean) 00 needle
Mains – #240-250
Air – 1-60 / sol2-50 / sol3-100

I think the change for the 60 was a good call.
Did not plug chop, but the inside of the silencer tube looked very good.
Very strong head wind in the straights. (I wonder what top speed the meter would show without wind), the SBK guys also complained about wind the past weekend.
Had a few almost brown happenings negotiating the high speed left before the chicane ;D
Wind is not nice when at the track...

Problems with low revs, low throttle persist...
Somewhere here someone caught me just before I went out to the track... loads of smoke... no power what so ever to push a start.
https://www.youtube.com/watch?v=PpgGiDqEe4M


Title: Re: 3MA trackbike project
Post by: jools on May 01, 2017, 11:01:44 PM
Thanks Rui

a nice selection of machines in your video link.  :)

I'm sure I recognise the green TZ250's from Spa....................??
Title: Re: 3MA trackbike project
Post by: casal-fan on May 08, 2017, 10:24:29 PM
Yes Jools.
My excursion into the gravel happened because I was gready, and tryed to overtake on the green TZ - mega bikes.
Nice machines present, some pics of some of the SP stuff present.
Title: Re: 3MA trackbike project
Post by: jools on May 08, 2017, 10:55:48 PM
LOL
often on the track we become a different person.................

I have one burning question that I been waiting to ask - why remove the TPS from the carbs and set it at a static position ?
Is there a problem if it is left as Yamaha intended, to follow throttle position ?

I can understand this if the complete VAJ system is removed (fixed air jet) but this seems to create problems with fuelling at certain throttle positions.

One thing to note on my original 3MA carbs, which I will be putting back on the bike now I have base settings, is that the throttle slide cutaways have been modified. Maybe this was the previous owners way of sorting out mid range richness ??
Title: Re: 3MA trackbike project
Post by: casal-fan on May 13, 2017, 09:54:02 AM
Jools, main reason is that my TPS is not working correctly.
I can select a voltage value and lock it, but when working together with the throttle mecanism, the values are nowhere near what Louis tested...
I tryed to post here on the wanted section, as well as sent PM to some people, but sofar no one had a spare, that they could part with.
Fixed did not work for me... or it did, but I find better performance from the engine runing locked WOT curve and TPS.
I belive that great things would happen if I could play with the hole puzzel (TPS dictating curve and airjets), but no have one. Ebay, never found one, unless buy complete carbset.

I have noticed your slide.
One of my thughts is that the slide cutaway is too high, wich allows air to pass on top of the needle jet at very low thottle openings, and enabling the needle circuit to start working and delivering fuel at very low throttle openings.
Your slides if I remember correctly are opened to the sides? This would allow more air to flow into the motor at low throttle settings, leaning it again at low throttle?
This is also what I feel I need.
But only a thought/theori, my thoughts/theori are in general - wrong ;D
We´ll see... its all good.

Title: Re: 3MA trackbike project
Post by: maccas on May 13, 2017, 11:55:29 AM
Rui i have a tps you can have. Pm me.

Dan
Title: Re: 3MA trackbike project
Post by: jools on May 14, 2017, 05:30:58 AM
i have just finished putting my original 3MA carbs back together.

The original needles are in the 3XV SP carbs on the bike but I had some new 6EN11-56 needles from the 3XV race bike I will try out.

I did notice that the 3MA TPS is mechanically different to the 3XV so bear that in mind. The plug was cut off mine so will have to come up with another method of wiring up - probably spade connectors is simplest.

I also dug out the VAJ block ready to try out when I get over there.

Just about to order some pilot jets and air jets for the VAJ if I can find them.............

are they anything like shown here ?

https://www.jetsrus.com/a_jets_by_carburetor_type/a_jet_kits_mikuni_selection.htm

Title: Re: 3MA trackbike project
Post by: casal-fan on May 15, 2017, 03:11:25 PM
Jools, the 3ma is full of surprises.
Might work, might not  ;D
At assen while warming the engine and the bike struggled a bit, a veteran told me that i should be carefull and jet up the bike sounded lean. i told him that if i jetted richer it would be worst. Did not have time to explain because i had to gear up... and he left, probably thinking i was stupid ;D
Will try to send a pic of the air jets.
Dan. You've got mail ????
I hope for good things to happen with a fully functioning tps
Title: Re: 3MA trackbike project
Post by: jools on May 24, 2017, 05:02:09 AM
I got a delivery of connectors from Eastern Beaver - surprised at their prices which are very cheap.
As I'm unsure of the pin outs of the VAJ, I'll take them with me to fit in the UK.
I couldn't find the correct size air jets so ordered smaller ones that I can drill out.
I also ordered 2 sets of pilot jets from here as the local Mikuni guys couldn't get any.
http://www.ebay.com.au/itm/182413344492?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
I'll compare them with others I have to see how accurate they are, at the price I have nothing to lose.
Title: Re: 3MA trackbike project
Post by: peterbike on May 24, 2017, 11:53:03 AM
 Jools unless you have a VERY special drill kit   :o  you will only get a so/so tune.
 These guys you can just email with your list , 3/4 days usually.
 http://www.showandgo.com.au/mikuni/mikuni.htm?mikuni_bf.htm~mainFrame   
 
    N100606 (airjet you need) 

 I would recommend buying a range,  starting at 30, then up in steps of 5 to 80 for starters. 
  eg. N100606      30 x 1, 35 x 1 etc.  up to 80

  Later you will probably need to double up on some & if you are real keen you can get into the 2.5's
 If you find you need to go bigger than an 80 then change the jet or needle height and start again at 30 is
 an option.
 They are only $8.00 each useable in 3XV & 3MA.
 If you hang them out the side , it is very easy access for changes.   ;)
 Childs play    ;D
Title: Re: 3MA trackbike project
Post by: jools on May 24, 2017, 10:54:41 PM
Peter

I  ordered a precision watchmakers drill bit kit to evaluate with sizes from .3mm up to 1.2mm with a hex shaft.

as the air jets I want to start with are 100 = 1.0mm. They drill will be mic'd up to check its accuracy and I have a jig made up to hold the jet in my lathe chuck to rotate by hand. Time will tell if it works.
Title: Re: 3MA trackbike project
Post by: jools on May 24, 2017, 11:01:25 PM
I just looked at their website - the N100*** is not the correct type for the VAJ

Its more like the BS30 style
Title: Re: 3MA trackbike project
Post by: paul8899 on May 24, 2017, 11:15:59 PM
I used 4mm brass grub screws when I altered the air jets, think they were £1.84 for ten
Title: Re: 3MA trackbike project
Post by: peterbike on May 25, 2017, 07:06:05 AM
 Jools, the N100606 is the correct airjet for a 3XV definitely -  I just checked my old receipts.
 Not sure on the 3MA, but was told they are the same.  (mine is in lock up - so cannot check)
 It is not pictured/listed on the website, you would need to ring or email to order.
 If not in stock then 1-2 weeks, but that only happened once to me.
 Tried the drill method but they must have been chinese - looked good, but no work ?

 I just rang show & go. They have no stock atm, but happy to order in.  About $10 each now.
 micheal is the guy i spoke to, he used to have a 3MA with PWK carbs on. - no airjets connected
 Said it used to flood under heavy braking, mmmm.. sounds like everyone else ?
 He also let it slip that they order from sudco.  Maybe cheaper ?
Title: Re: 3MA trackbike project
Post by: jools on May 25, 2017, 08:04:59 AM
Jools, the N100606 is the correct airjet for a 3XV definitely -  I just checked my old receipts.
 Not sure on the 3MA, but was told they are the same.  (mine is in lock up - so cannot check)
 It is not pictured/listed on the website, you would need to ring or email to order.
 If not in stock then 1-2 weeks, but that only happened once to me.
 Tried the drill method but they must have been chinese - looked good, but no work ?

 I just rang show & go. They have no stock atm, but happy to order in.  About $10 each now.
 micheal is the guy i spoke to, he used to have a 3MA with PWK carbs on. - no airjets connected
 Said it used to flood under heavy braking, mmmm.. sounds like everyone else ?
 He also let it slip that they order from sudco.  Maybe cheaper ?
3MA are different - well on mine anyway - fiddly little buggers. re ordering: I got the same response from Mikunioz. But Mikuni out of stock (for pilot jets anyway) with no dates given. I need mine quickly hence the drilling option
Title: Re: 3MA trackbike project
Post by: loor on May 26, 2017, 05:10:48 AM
Peter

I  ordered a precision watchmakers drill bit kit to evaluate with sizes from .3mm up to 1.2mm with a hex shaft.

as the air jets I want to start with are 100 = 1.0mm. They drill will be mic'd up to check its accuracy and I have a jig made up to hold the jet in my lathe chuck to rotate by hand. Time will tell if it works.

Sorry mate but the Jets are metered with flow and not by diameter. For example a Full mainjet size enrichens by 8%. The metering method also applies to the vaj Jets. So #100 is not 1mm.
Because I also wanted to be able to make my own Jets to play I measured the flow by time through the existing genuine Jets and extrapolated that in a excel sheet. I'll see if I can dig that up

Cheers

PS I think that's the wrong thread for this conversation....
Title: Re: 3MA trackbike project
Post by: casal-fan on May 26, 2017, 12:57:30 PM
Loor, hope it is OK.
I took the Liberty of posting your research.
Your research goes pretty much hand with hand with my findings, both by looking at hole size, as well as feeling for performance on the bike.

Mikuni numbers are much more accurate.
Basically a 1.9mm hole flows near twice as much as a mikuni #190

Hope it is OK Loor.
Title: Re: 3MA trackbike project
Post by: loor on May 26, 2017, 06:07:42 PM

Hope it is OK Loor.

It certainly is. Thanks for posting I couldn't find it on my phone anyways.
Title: Re: 3MA trackbike project
Post by: jools on May 27, 2017, 04:15:50 AM
is that still applicable for air jet sizes though ?
Title: Re: 3MA trackbike project
Post by: loor on May 27, 2017, 07:11:00 AM
I measured the flow through the 3 Jets I had (see the dots) and then connected the dots with a line. While flow/time should be a constant (in my mind) I think it should be applicable to all Jets but I'm not sure tho.

Maybe some interesting reading:
http://www.rd350.gmxhome.de/jet_size_problem_english.pdf
Title: Re: 3MA trackbike project
Post by: jools on May 27, 2017, 07:35:22 AM
Loor, hope it is OK.
I took the Liberty of posting your research.
Your research goes pretty much hand with hand with my findings, both by looking at hole size, as well as feeling for performance on the bike.

Mikuni numbers are much more accurate.
Basically a 1.9mm hole flows near twice as much as a mikuni #190

Hope it is OK Loor.

Looking at that flow graph it would appear that the correspondence between jet diameter and jet number is midway between the upper and lower lines, which will likely be the nominal value/size. As has been mentioned accuracy of the hole at these sizes calls for a higher than expected tolerance and without comparable flow rates its unwise to comment further  :o.
This data does bear out what I have discovered using precision drill shanks as go/no go checks of the few air jets I have and leads me to be confident that a 1.0mm drill, as checked with a micrometer, should equate to a #100 air jet dependent on drilling accuracy and tolerance.

Not wishing to clog  Rui's thread further I will be continuing this approach on my 3MA thread  ;)
Title: Re: 3MA trackbike project
Post by: casal-fan on May 27, 2017, 09:34:10 AM
No clog, no problem  :)
Relating metric to mikuni size has been on my list for some time. I got to compare a 1.25 bore does not pass trough a 130.
Going bigger and the difference in hole size is obvious just like loors graph suggests.
Pic is a 200 mikuni and a 2 mm bored air jet.
Title: Re: 3MA trackbike project
Post by: Martin77 on May 27, 2017, 11:07:08 AM
I found this very useful chart when I started drilling out jets for the 125, though if Mikuni use this also for airjets I have no idea.

Jet Size CC/Min Jet bore
10 0.273
15 0.335
20 0.387
25 0.432
30 0.474
35 0.511
40 0.547
45 0.580
50 0.611
55 0.641
60 0.670
65 0.697
70 0.723
75 0.749
80 0.773
85 0.797
90 0.820
95 0.843
100 0.865
105 0.886
110 0.907
115 0.927
120 0.947
130 0.986
140 1.023
150 1.059
160 1.094
170 1.127
180 1.160
190 1.192
200 1.223
210 1.253
220 1.282
230 1.311
240 1.339
250 1.367
260 1.394
270 1.421
280 1.447
290 1.472
300 1.498
310 1.522
320 1.547
330 1.571
340 1.594
350 1.617
360 1.640
370 1.663
380 1.685
390 1.707
400 1.729
410 1.751
420 1.772
430 1.793
440 1.814
450 1.834
460 1.854
470 1.874
480 1.894
490 1.914
500 1.933
510 1.953
520 1.972
530 1.990
540 2.009
550 2.028
560 2.046
570 2.064
580 2.082
590 2.100
600 2.118
610 2.135
620 2.153
630 2.170
640 2.187
650 2.204
660 2.221
670 2.238
680 2.255
690 2.271
700 2.287
710 2.304
720 2.320
730 2.336
740 2.352
750 2.368
Title: Re: 3MA trackbike project
Post by: jools on May 28, 2017, 12:14:50 AM
Thats a lot of work typing that Martin  ^-^
Title: Re: 3MA trackbike project
Post by: jools on May 28, 2017, 12:23:02 AM
No clog, no problem  :)
Relating metric to mikuni size has been on my list for some time. I got to compare a 1.25 bore does not pass trough a 130.
Going bigger and the difference in hole size is obvious just like loors graph suggests.
Pic is a 200 mikuni and a 2 mm bored air jet.

That is what leads me to believe there is no direct comparison between main/pilot jets and air jets.
in my examination of the 150 air jet from the VAJ 1.5mm (nominal) drill for me was the correct drilling.
Maybe thats just a coincidence of where the lines of a similar air flow graph would cross ?
Even so anything "close' to that jet size could be drilled with reasonable confidence  ???

(Yes, I know jets are cheap but try getting hold of the correct sizes in a hurry! From ordering to receiving from the Mikuni dealers in Oz took 2 weeks and they still could not get the pilots and air jets I specifically wanted)
Title: Re: 3MA trackbike project
Post by: jools on May 28, 2017, 08:07:28 AM
Jools, the N100606 is the correct airjet for a 3XV definitely -  I just checked my old receipts.
 Not sure on the 3MA, but was told they are the same.  (mine is in lock up - so cannot check)
 It is not pictured/listed on the website, you would need to ring or email to order.
 If not in stock then 1-2 weeks, but that only happened once to me.
 Tried the drill method but they must have been chinese - looked good, but no work ?

 I just rang show & go. They have no stock atm, but happy to order in.  About $10 each now.
 micheal is the guy i spoke to, he used to have a 3MA with PWK carbs on. - no airjets connected
 Said it used to flood under heavy braking, mmmm.. sounds like everyone else ?
 He also let it slip that they order from sudco.  Maybe cheaper ?
3MA are different - well on mine anyway - fiddly little buggers. re ordering: I got the same response from Mikunioz. But Mikuni out of stock (for pilot jets anyway) with no dates given. I need mine quickly hence the drilling option

I have to go cap in hand and apologise to Peter as the air jets are indeed N100.606 as he advised after all - not sure which photo I was looking at but I thought that number was the round main jet............. :o
I'll be a bit more careful opening my mouth in future  ^-^
Title: Re: 3MA trackbike project
Post by: vinny on June 04, 2017, 08:57:53 AM
I found this very useful chart when I started drilling out jets for the 125, though if Mikuni use this also for airjets I have no idea.

Jet Size CC/Min Jet bore
10 0.273
15 0.335
20 0.387
25 0.432
30 0.474
35 0.511
40 0.547
45 0.580
50 0.611
55 0.641
60 0.670
65 0.697
70 0.723
75 0.749
80 0.773
85 0.797
90 0.820
95 0.843
100 0.865
105 0.886
110 0.907
115 0.927
120 0.947
130 0.986
140 1.023
150 1.059
160 1.094
170 1.127
180 1.160
190 1.192
200 1.223
210 1.253
220 1.282
230 1.311
240 1.339
250 1.367
260 1.394
270 1.421
280 1.447
290 1.472
300 1.498
310 1.522
320 1.547
330 1.571
340 1.594
350 1.617
360 1.640
370 1.663
380 1.685
390 1.707
400 1.729
410 1.751
420 1.772
430 1.793
440 1.814
450 1.834
460 1.854
470 1.874
480 1.894
490 1.914
500 1.933
510 1.953
520 1.972
530 1.990
540 2.009
550 2.028
560 2.046
570 2.064
580 2.082
590 2.100
600 2.118
610 2.135
620 2.153
630 2.170
640 2.187
650 2.204
660 2.221
670 2.238
680 2.255
690 2.271
700 2.287
710 2.304
720 2.320
730 2.336
740 2.352
750 2.368
Thanks for this Martin exactly what I need :)
Title: Re: 3MA trackbike project
Post by: casal-fan on June 20, 2017, 12:46:41 AM
Been at the track this weekend.
Loads of other things going on, so I just put fresh fuel and went for it.
Mixed feelings... I used most of the few time available (missed a lot of trainning because of rain) to test suspension, tyres - the metzeler racetech rr, and gearing.
Try to make a little summary.
Day1 - Rain in the morning, missed 2 out of 3 quali sessions.
           In one session of 15m got time, but then rain didn´t allow to ride at the race. Got some laps with different settings

Day2 - Missed again some quali time but got 55 out of 120.
           Bike was starting to missfire.
           To the race... a s.plug fouled. Went in the pit after seight lap on one cylinder... surt show
           But got some track time left to test some gearing options as well as suspension.
           Tyres felt good at around recomended pressures 2.3-4 bar front - 1.7 rear

One a footnote.
Still looking desperatly after a 3MA TPS sensor. Dan doen´t seem to be able to locate his spare.


Title: Re: 3MA trackbike project
Post by: jools on June 20, 2017, 06:09:32 PM
I may be able to help ????
I will pm you later.
Title: Re: 3MA trackbike project
Post by: casal-fan on June 21, 2017, 07:32:04 PM
Nice of you Jools, thanks (-P)

Got a shot of the rear tyre.
They are Metzeler racetch RR K2 rear, and K1 front.
Performance is very good.
Stability and ride ease increased a lot, good results on suspension setup.



Title: Re: 3MA trackbike project
Post by: jools on June 21, 2017, 10:48:58 PM
Are you using the 18" rear wheel ?
Title: Re: 3MA trackbike project
Post by: casal-fan on June 22, 2017, 12:42:56 AM
No Jools.
VJ22 4.5" with 160/60
Front is also suzuki 3.5" with 120/70.
Quality rubber with these sizes available (-P)
Title: Re: 3MA trackbike project
Post by: jools on June 22, 2017, 08:32:32 AM
Yes,
I'm using std 3MA front and 3XV rear with Pirelli SC1's - 110 front and 150 rear - (I think  :))
Title: Re: 3MA trackbike project
Post by: casal-fan on June 28, 2017, 11:42:49 PM
Replacement of s.plug and cap. I´d been neglecting this... and it has probably at some degree perhaps contributed to the persistent problems.
Found these at a local kart shop.
Short brisk iridium and pvl short cap to match.
Ginea pig for this setup on a 3MA I supose... but these have been tested, used and abused by the 125 karting kids to death, don´t see why they shouldn´t work.
Title: Re: 3MA trackbike project
Post by: casal-fan on July 15, 2017, 10:34:04 PM
TPS drought is over.
2 from ebay, and got one at the post office waiting for collection.
Next outing mid august  (-P)
Title: Re: 3MA trackbike project
Post by: jools on July 16, 2017, 09:03:48 AM
LOL

did the one I posted turn up ?
Title: Re: 3MA trackbike project
Post by: casal-fan on July 16, 2017, 08:26:13 PM
Yes Jools (-P)
I´ll measure it against the others.
If not eeded, I´ll send it back. (-P)

Cheers
Rui
Title: Re: 3MA trackbike project
Post by: jools on July 17, 2017, 12:31:37 AM
 (-P)

Lets see how close they all are - some calibration instructions would be nice  ;)
Title: Re: 3MA trackbike project
Post by: casal-fan on July 17, 2017, 11:59:26 AM
(-P)

Lets see how close they all are - some calibration instructions would be nice  ;)

Jools, our friend Louis has established the TPS voltage ranges for the different curves as well as VAJ operation.
http://www.tzr3ma.com/tps-sensor.html

While Louis research was based on a 10 CDI, I think the 00 one won´t be much different. TPS part number is the samme.

Fine calibration would be possible by having the TPS delaying/advancing the map/vaj chart switch by adjusting the tps in the slots.
We´ll see how it goes.
My guess, and its just a guess.
The extra advance as well as the vaj giving more air at low revs/low gas openings will do a bunch of good with my flooding problem, wich is what the problem is.
The intake spacers are comming out, besides a member here wich I consider as highly 3MA educated urging me to try without the spacers and see how it goes, Louis also reported (I think I read it somewhere, not sure) the flooding problem to the worst with intake spacers (tryed to find Louis writting on this yesterday but no luck, but I´m quite sure he made this relation.

We´ll see how it goes... (-P)
Title: Re: 3MA trackbike project
Post by: loor on July 17, 2017, 12:52:12 PM
Hey Rui,

do you know if there are more than two TPS / VAJ maps stored in the ECU? I wrote Louis a pm but he didn't reply to my questions, maybe he's busy ;)

I think it should be possible to make a kind of VE table to see how the changes effect the VAJ system.

Cheers


Edit: something like that: https://www.dropbox.com/s/hskfxr4yr5m7z7h/3ma-vajmap.xls?dl=0

you can change the values of the VAJ jets on the left and will see the changes on the table right. The table was created by the values i found on Louis' homepage (cdi-facts/solenoid-map) i'm not sure if the tps1 map is correct at 25% throttle.

cheers!
Title: Re: 3MA trackbike project
Post by: casal-fan on July 17, 2017, 03:44:13 PM
Hej Lorenz

Most of my starting points, or how does it work has come from the vast research Louis has done.
To that I added a bit of my own... mostly small things.
But, talking VAJ for instance, there is a link between louis testing and how I see the machine functions.
I do not use the std. jets in the VAJ block.
I have been using the full throttle curve+2* with VAJ connected with customs jetting, so full throttle curve is pretty much sorted, as I have the main jet together with air correction working pretty good.
Based on Louis research and my own findings with small lamps connectd to tps powercales, wich give the same results, full working TPS is maybe what I am missing to have this bike tuned to run good at all circunstances. Maybe, perhaps... ;D

About your questions, Louis has establised that there are four maps based on TPS position.
The values measured by Louis are very close to the well known 3MA ignition advance map that shows up on internet, so no point doubting that.
Air correction basically decreases with higher rpm and/or higher throttle.

Cheers
Rui
Title: Re: 3MA trackbike project
Post by: loor on July 17, 2017, 04:15:24 PM
About your questions, Louis has establised that there are four maps based on TPS position.
The values measured by Louis are very close to the well known 3MA ignition advance map that shows up on internet, so no point doubting that.

Hey Rui,

its not about the doubt, its about the actual values for us to optimize our systems. if you feel a flat spot at given rpm/throttle you can play around with the jets virtually without buying stuff / getting your hands dirty.  ^-^

Air correction basically decreases with higher rpm and/or higher throttle.

Unfortunately not if you look at TPS1 curve at 12-13000rpm :-(
Title: Re: 3MA trackbike project
Post by: jools on July 17, 2017, 10:50:20 PM

Jools, our friend Louis has established the TPS voltage ranges for the different curves as well as VAJ operation.
http://www.tzr3ma.com/tps-sensor.html
Fine calibration would be possible by having the TPS delaying/advancing the map/vaj chart switch by adjusting the tps in the slots.

Yes - I remember discussing this, I meant calibration in terms of static setting of resistance readings for 0 and full throttle positions, as we don't all have access to Louis' sophisticated laboratory  :)) This what the slots are for initially then once they are set to factory specs and marked, it may be possible to play with the settings.


We´ll see how it goes.
My guess, and its just a guess.
The extra advance as well as the vaj giving more air at low revs/low gas openings will do a bunch of good with my flooding problem, wich is what the problem is.
The intake spacers are comming out, besides a member here wich I consider as highly 3MA educated urging me to try without the spacers and see how it goes, Louis also reported (I think I read it somewhere, not sure) the flooding problem to the worst with intake spacers (tryed to find Louis writting on this yesterday but no luck, but I´m quite sure he made this relation.

We´ll see how it goes... (-P)
[/quote]
I did remove my spacers, mainly to try and accommodate the airbox within the TZ fairing, but I believe it had a positive effect and the fuel build up problem was not evident at Spa. With the engine running too rich at main jet I would have expected the fuel build to be more of a problem.............

Title: Re: 3MA trackbike project
Post by: casal-fan on July 17, 2017, 11:17:24 PM

Yes - I remember discussing this, I meant calibration in terms of static setting of resistance readings for 0 and full throttle positions, as we don't all have access to Louis' sophisticated laboratory  :)) This what the slots are for initially then once they are set to factory specs and marked, it may be possible to play with the settings.

Yes Jools, this would somehow be like playing with needle settings without all the hardwork+ignition timing would follow... seen this, but perhaps a bit time consuming to test to full extent. But it will be considered acording to how the engine runs (-P)



I did remove my spacers, mainly to try and accommodate the airbox within the TZ fairing, but I believe it had a positive effect and the fuel build up problem was not evident at Spa. With the engine running too rich at main jet I would have expected the fuel build to be more of a problem.............

You mean fuel buildup was less without spacers???
Title: Re: 3MA trackbike project
Post by: casal-fan on July 17, 2017, 11:43:38 PM
About your questions, Louis has establised that there are four maps based on TPS position.
The values measured by Louis are very close to the well known 3MA ignition advance map that shows up on internet, so no point doubting that.

Hey Rui,

its not about the doubt, its about the actual values for us to optimize our systems. if you feel a flat spot at given rpm/throttle you can play around with the jets virtually without buying stuff / getting your hands dirty.  ^-^

Air correction basically decreases with higher rpm and/or higher throttle.

Unfortunately not if you look at TPS1 curve at 12-13000rpm :-(

Lorenz, good point.
I think on my bike, flat point has had to do with incorrect fueling at a stating condition, like warming up the engine, or wainting for a light to go of at te track with the engine running. Cold engine is even worst. Once it gets going... it goes :)
No flat spot at 8 or 9 anymore because at WOT settings when the engine runs clear its smoth, carburation and air correction at WOT are acceptable.
But, the numbers I use... are probably useless to others. My pipes for instance are probably a one off :D, my airbox setting is also not far from std. while most adopt not using the airbox or at least remove the intake trupets.

About the TPS curves... think is not easy... my bike runs better with full throttle curve, but it is my bike and (the little) I can achive jettingwise :-\
Others are maybe different...
Loor, 12-13000 CDI rpm is a lot of rpm. While trying different gearing last time out, there was a part of the circuit was using second overrevving to 13000 tacho rpm because shifting would not be convenient... Sounded good :) and was only 4-5 laps, but the machinery felt and sounded quite stressed at 13000 overrev. Gearing was not suited.

All good fun, we´ll see (-P)
Title: Re: 3MA trackbike project
Post by: casal-fan on August 10, 2017, 09:04:26 AM
2 trackdays with 2 races the coming weekend.
Man… I´ve been busy with other things, no place to work on the bike (garage filled with moving boxes), so its not easy. 10-15 minuttes to find a spanner is not optimal ;D
Managed to test the 2 tps sensors I got from ebay. Got the proof for my suspition that my TPS was defect. Voltage on the 2 new TPS is the same if position is the same and the voltage range for each ignition curve is within Louis voltage numbers – so that’s good.

Jools - the TPS you sent is 3XV???
I could not couple it to the mecanism on the 3MA carbs.

The intake spacers are out – had the chance to look at the sagging of the sealant I used last time – Attention guys, while intake was torqued to spec, some places it was the sealant liquidgasket that was sealing – not the papergasket (this problem has been discussed here) – make sure to put enough liquid sealant in the right places when working with the intake system.

Still a lot of things to do before bike is ready, and no time to do it – but this is nothing unusual.
Gearing, lubing, carbs tjeck, fuel heights, sinchro, etc etc
I´ll take some pics later today if I have the chance.
While I know that changes are always unknown if it will work or not, I am confident (-P)
The best scenario is that on Monday I´ll write here how good the bike is and post the specs I usued(-P)

Cheers
Rui

Title: Re: 3MA trackbike project
Post by: casal-fan on August 10, 2017, 11:59:35 PM
TPS calibration.
About the middel of Louis values.
Title: Re: 3MA trackbike project
Post by: jools on August 11, 2017, 02:11:53 PM

Yes - I remember discussing this, I meant calibration in terms of static setting of resistance readings for 0 and full throttle positions, as we don't all have access to Louis' sophisticated laboratory  :)) This what the slots are for initially then once they are set to factory specs and marked, it may be possible to play with the settings.

Yes Jools, this would somehow be like playing with needle settings without all the hardwork+ignition timing would follow... seen this, but perhaps a bit time consuming to test to full extent. But it will be considered acording to how the engine runs (-P)



I did remove my spacers, mainly to try and accommodate the airbox within the TZ fairing, but I believe it had a positive effect and the fuel build up problem was not evident at Spa. With the engine running too rich at main jet I would have expected the fuel build to be more of a problem.............

You mean fuel buildup was less without spacers???

Sorry Rui I  missed this, but yes it did appear to be better but with all my other problems that weekend it may have been masked or will reappear once I get the main jet correct and have to re compensate the mid range.............that is why I will be trying the powerjets.
Title: Re: 3MA trackbike project
Post by: jools on August 11, 2017, 02:20:07 PM


Jools - the TPS you sent is 3XV???
I could not couple it to the mecanism on the 3MA carbs.





Yes, did I not mention that ?  :o sorry - it is the fixed dummy one I use on my 3MA with the 3XV SP carbs. Does it not mount to the 3MA bracket ? I never checked to be honest.  :-\
Title: Re: 3MA trackbike project
Post by: casal-fan on August 21, 2017, 09:32:50 AM
No Jools, its not the same attaching system.
I´ll send it back, please send me your adress.

Been a bit busy, but own youguys a little report from the last outing.
The 3MA rode for about 20 minutes before it holed a piston. Little hole, but a hole anyways :(
No panic or nothing, it just started loosing power down the straight, clutch in, and when I came to a holt, engine still running, but it was a 125cc
Had the change to try the tps and start from a stand still situation, and it was MUCH better.
The hole in the piston was my fault… I knew jetting at the top was good for this track when 15-18 degrees, but this morning was cold, very cold.
New piston as well as rings for the other one are already ordered in Italy.
I´ll change the piston, give it a major clean up, jet a bit richer… and then… I´ll have to think about it.
I have the complete TZR series. Nice, but I´m not really the collector type, so perhaps 3MA and 2MA are coming up for sale. Will have to think about it.

Back to the race weekend.
I ended up borrowing a 99 bone stock R6 on street tyres. In all my live i´ve ridden a 4stroke for something like half an hour or so.
10 minutes practice on the R6… and then I got thrown to the wolves in a wet race on a bike I´ve practiced on for 10 minutes and with a tottaly different engine character to what I´m used to.
Went Ok, ended up 3rd last or something.
Sunday, still with the R6… it was fast, even in a short straight, the 600ccs gain considerably on the 250 2 stroke, but the R6 was no fun at all, not compared to a Little 2stroke.
Race Sunday. I´m the guy outbreaking an opponent  on the inside from 4.47 and then we disappear at 4.51
Went good, and I can understand with a lot of people choose the 4strokes, they just ride… but are booring as hell.

https://www.youtube.com/watch?v=z32QVFrsdy0

This kind of ends this chapter regarding the 3MA.
If all goes after plan, I´ll have a single cylinder 250cc stroke cagiva/gasgas hybrid for NeXT year and the 3MA will not be used.
My impressions are that the 3MA is a good bike, a very good bike. Very stable, easy to extract decent power of.
On the other side, it is big(ish), heavy and quite hard to setup carburation wise.
I had fun running it... and the sound of a 3MA pushing 6th at full tilt 12000 rpm... well, its just glorious (-P)
Title: Re: 3MA trackbike project
Post by: jools on August 22, 2017, 05:19:05 AM
Rui

I hope after some time resting you will re-consider the 3MA.
Frustrating Bastard of a bike but also nice and easy to ride and a good fit for my large frame. ^-^

I will pm you sons address in UK as that is where the bike lives now.

I thank you for sharing all of your reports and videos, information and frustration with us.
Maybe we will catch up one day  (-P)

Jools
Title: Re: 3MA trackbike project
Post by: casal-fan on February 13, 2018, 01:23:35 PM
So, fellow 3MA enthusiasts.

Life has gotten in the way, and another much needed track machine is still in project fase.
This means that the 3MA is the nearest I have at hand to take a couple of rounds around a track this year.
Plans are for the engine to come out (again again), inspection work as well as some repairs are needed.
New piston – cylinder inspection – new balanceshaft bearings as well as a new power output bearing are probably necessary, as the engine started developing a slight whynning noise. Will have to check that.

As for the running difficulties… well, thinking of trying a hole new approach because it seems that the setups I´ve been running are far away from perfect.
I have read the 3MA sugo kit thread a couple of times as well as the special book, VERY big thanks to the members that so kindly uploaded those… and have some thoughts about it…
Basically, I am assuming that the carb settings given by the sugo manual for SP setup (not the bit written in hand), are planed for the 3MA1 – 1989 – TM32 carbs (sugo manual page 15 (page 35 on the pdf)).

After reading the 3MA sugo manual post, I believe Warwick made a comment I pretty much agree with. People are mistaking what SP stands for in the manual. SP was probably the name of the race series and has nothing to do with the TZR3MA-SP that came in 1990.

Interesting, interesting… we´ll see what time brings, but as things stand now the 3MA is the one to bet on to have ready sometime around midsummer.

By the way, looking at the jetting specs for the SP class (as well as F3 for that sake) the combo needle jet/needle massively choke the engine for fuel in relation to the road model – interesting…
I tried a mikuni needle (7-series for large 38mm mikuni carbs), and fuel building was no more… unfortunately the engine blew up after a few laps with this setup ;D

We´ll see what future brings (-P)
Title: Re: 3MA trackbike project
Post by: kischde on February 13, 2018, 01:44:46 PM
If I remember right (which can be wrong, as I am now aged 45+) SP was the Sport Production Class (nowadays known as Stock-Sport Class) and FIII was the "open one". In the SP they've been running also the NSR etc against the 400cc four stroke. The bikes had to be more or less stock.
In the FIII they've been running without airbox etc...
These bikes where also running at IoM for example, and in a country I can't remember they've organized a cup with the 3MA's (SP Class).

BTW, this was the reason for me to go with TM32 (no SS) and open airbox.. I hope these values in the sugo manual will be a good way to start jetting
Title: Re: 3MA trackbike project
Post by: casal-fan on July 24, 2018, 02:08:32 PM
Found a video of nice 2strokes at the Assen TT circuit.
The 3MA flooding Assen with engine sound. Pushing 3rd-4-5-6 from 1.52 to 2.05
Some really nice bikes at full revs (-P)

https://www.youtube.com/watch?v=8GH8XKevtRQ
Title: Re: 3MA trackbike project
Post by: casal-fan on February 01, 2019, 01:53:27 PM
Other project trackbikes taking longer to complete then expected.
This means that the 3MA Will get yet another chance, sooner then expected...
We'll see how IT goes...

Mikuni parts arrived - the closest one can get to sugo setup without the sugo needles, wich mikuni No longer can deliver.
Setters, needles, original mikuni pilots.
I Was lucky enough that Maccas found a set of original air adjustment screws wich he sent to me, so now the carbs can not be blammed, All original mikuni stuff inside.

Crossing my fingers...
While the bike goes good when IT finally gets going, IT can not accelerate when the flag goes down, because it has gotten charged Up with fuel on the grid.
No good at All, frustrating and dangerous...
Will update as I go... Slowly (-P)
Title: Re: 3MA trackbike project
Post by: jools on February 05, 2019, 03:39:30 AM
Hi Rui,

how close are those 6EN11-56 to the SP needles ? (in your opinion)

regards

Jools
Title: Re: 3MA trackbike project
Post by: Louis on February 05, 2019, 07:29:34 PM
Hello Rui,

On my road going 3MA I ride with P8 and stock (3MA1) needles on lowest position (leanest possible)
The charging up with fuel is almost gone, that sounds nice but it is just a indication how lean this setup is.
For road going purpose you can control it, by monitoring the EGT closely. (give some throttle and let it pull if its getting to high)

But I don't know how it goes when you have a fast corner at the circuit and you slow down on the throttle at about 10.000rpm
Do you use the oilpump or premix?

Title: Re: 3MA trackbike project
Post by: casal-fan on February 06, 2019, 11:09:34 AM
Louis, yeah... my 3MA also responded very good to a drastic lean needle/needle jet combination that I had the year you and your dad came to Assen... This was with std. jetsetter and a series 7 or 8 mukuni needle wich is much larger then 6 series that are used as standart.
This was a bit too lean because I was lean related throttle response, but this was different then the charging up problem, but it was for me, a test that provede that a lean needle setup can help.
Unfortunetly it was a short pleasure, because the crank, as you know, went west after some laps ::) ::)

Jools, haven´t run the data for the SP needle.
Don´t think it is present on the mikuni chart I got from mikuni germany.
I did compare the 3MA1-needle to the Sugo needle, and the sugo needle compared to the 6EN11-56.

The 6EN11-56 on the full rich notch on a P2 setter compares very well with the leanest sugo setup possible.
You can see a study on them here.
 http://pure2strokespirit.net/forums/index.php?topic=5684.0

We´ll see how it goes...
Title: Re: 3MA trackbike project
Post by: jools on February 06, 2019, 11:39:52 PM
Rui,

I probably already have some 6EN11's somewhere but I went ahead and ordered 3 pairs and some P# needle jets too from Allens to be delivered to my son's house in Spondon, where the bike lives.

(I'll have to teach him how to put a 2 stroke back together to save me time when I get over there ^-^)

One thing that I have just considered is the effect of removing the intake adaptors I made up to suit the 3XV Sp carbs and which effectively space the reed valve 10mm away from the cases.
Title: Re: 3MA trackbike project
Post by: casal-fan on March 17, 2019, 12:39:06 PM
The 3ma can trully be a bike that pushes the limits of human perseverance.
Drained for fuel before storange... But it still manages to drip ;D