Author Topic: 3MA trackbike project  (Read 30530 times)

casal-fan

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Re: 3MA trackbike project
« Reply #30 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 redandblues 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??? ?:-|

casal-fan

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Re: 3MA trackbike project
« Reply #31 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.

Wont 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...
« Last Edit: December 28, 2014, 12:42:03 AM by casal-fan »

Louis

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Re: 3MA trackbike project
« Reply #32 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


The 105 mod seems to cut away a total off 27,5mm


Your Casal mod 8) takes away 40mm


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

Cheers


King off all twostrokes ''TZR250 3MA''

casal-fan

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Re: 3MA trackbike project
« Reply #33 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??? Dont 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...

casal-fan

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Re: 3MA trackbike project
« Reply #34 on: November 11, 2014, 10:09:13 PM »
Ive 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 wasnt looking for dead accuracy on the timing measurements since I was not changing them anyway. Belive the timing is good for what Im 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 isnt ;D
Just 10-12 rounds at very low speed)

« Last Edit: November 15, 2014, 10:13:39 PM by casal-fan »

Louis

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Re: 3MA trackbike project
« Reply #35 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
King off all twostrokes ''TZR250 3MA''

maccas

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Re: 3MA trackbike project
« Reply #36 on: November 11, 2014, 11:57:19 PM »
Great work Rui! Really interesting stuff regarding the pipes!

Dan

casal-fan

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Re: 3MA trackbike project
« Reply #37 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 your 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 Ive seen it, and Im thinking spacers yes.

« Last Edit: November 12, 2014, 11:08:42 PM by casal-fan »

Louis

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Re: 3MA trackbike project
« Reply #38 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.


I came at 215mm :)


King off all twostrokes ''TZR250 3MA''

casal-fan

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Re: 3MA trackbike project
« Reply #39 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 Ill 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 its 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. Ive 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. Ive 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, Ill 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 dont have pictures, it never happened." Isnt that what they say?
Unfortunatly my phones bat when out and I didnt take as many as I would like to have done.
« Last Edit: November 15, 2014, 10:19:37 PM by casal-fan »

casal-fan

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Re: 3MA trackbike project
« Reply #40 on: December 28, 2014, 03:35:03 AM »
Had a couple of hours today to drive to the garage.
Ive had the pipes soaking with caustic soda for about 1 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 Im 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
« Last Edit: December 28, 2014, 03:39:10 AM by casal-fan »

Louis

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Re: 3MA trackbike project
« Reply #41 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 Im 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
King off all twostrokes ''TZR250 3MA''

Warwick

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Re: 3MA trackbike project
« Reply #42 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 :).
Still Smoking...

casal-fan

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Re: 3MA trackbike project
« Reply #43 on: December 28, 2014, 10:56:35 PM »
Hi Louis.
Well 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... well see how it goes...

Warwick, thanks man... that one was picking my brain.

casal-fan

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Re: 3MA trackbike project
« Reply #44 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.