Author Topic: 3MA trackbike project  (Read 30537 times)

casal-fan

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3MA trackbike project
« 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 havenīt 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 Iīm sure about. Time to start reading...




maccas

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Re: 3MA trackbike project
« Reply #1 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

Need4speed

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Re: 3MA trackbike project
« Reply #2 on: May 04, 2014, 08:28:18 PM »
no dont know it..
4 Strokes are full of parts - 2 strokes are full of speed...

ybk

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Re: 3MA trackbike project
« Reply #3 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..

Louis

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Re: 3MA trackbike project
« Reply #4 on: May 05, 2014, 07:25:24 PM »
Great looking start, You will love it 8)
King off all twostrokes ''TZR250 3MA''

Edd

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Re: 3MA trackbike project
« Reply #5 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
TZR 250 3MA1
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41juergen

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Re: 3MA trackbike project
« Reply #6 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

casal-fan

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Re: 3MA trackbike project
« Reply #7 on: May 06, 2014, 09:18:10 PM »

I still havenīt seen the bike. Itīs at a friends garage, and Iīll 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 ?:-|
Iīll have to wait and see... Would prefer a 1 model engine form what I have read... wich wasnīt 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 wonīt be that easy. Iīve noticed a lot of people struggle there. My task will be somehow easyer, because the bike doesnīt have a tittle and will only se action in closed circuit.
I always start by saying to myself Iīll keep things stock... havenīt succeded yet ;D. Weīll 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. Itīs great. Your own dyno shead. How cool is that!
Followed with interess you testing with locked TPS. A shame you havenīt tryed the 0-1/8 curve with 3-4 degrees less advance.
Ybk, thanks. What used to be my 3XV I think itīs 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.

Louis

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Re: 3MA trackbike project
« Reply #8 on: May 06, 2014, 09:41:20 PM »
Quote
Been looking at your site Louis. Itīs great. Your own dyno shead. How cool is that!
Followed with interess you testing with locked TPS. A shame you havenīt 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
King off all twostrokes ''TZR250 3MA''

casal-fan

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Re: 3MA trackbike project
« Reply #9 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, Iīll 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 Iīll use that information.
There is one mod. though I havent seen done yet, and I think Iīll 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 donīt 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...  Iīll try to document everything I do the best I can, with as much pics I can, and hopefully by next sommer Iīll 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 :)








Edd

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Re: 3MA trackbike project
« Reply #10 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
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RZ 350 Hybrid
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casal-fan

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Re: 3MA trackbike project
« Reply #11 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!

Louis

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Re: 3MA trackbike project
« Reply #12 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 Iīll 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 donīt want to affect so much the effective operanting range of the powervalves...

Some info:
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


« Last Edit: May 24, 2014, 11:44:07 PM by Louis »
King off all twostrokes ''TZR250 3MA''

casal-fan

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Re: 3MA trackbike project
« Reply #13 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 Iīll 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.

Weīll see...

casal-fan

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Re: 3MA trackbike project
« Reply #14 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 donīt 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.