I think 2 thousandths is way too tight for an air cooled motor. I would double that in an air cooled motor.
At The Back Of The Pack
Arm chair racerFirst time rider
I think 2 thousandths is way too tight for an air cooled motor. I would double that in an air cooled motor.
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Wiseco is the best brand is it not? But yeah, thats all I've been using.Originally Posted by Dirtcrasher
83' 250R
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Arm chair racerNew to the board
I would think the shop I took it to would know the right tolerances, I've been taking my bikes to him for close to 20 years. Any pros around to throw in their .02?
83' 250R
At The Back Of The Pack
Arm chair racerFirst time rider
I run my water cooled R at 2 and a half to 3 thousandths, which is the clearance stated directly on the Wiseco box. If I need to run the motor hard immediately I will do up to 4 to 4 and a half thousandths.
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I second that, the shop that bored my Gf's blaster told me that as well, and it hasnt skiiped a beat and she runs the hell out of it.
Power User
Got the holeshot
that plug looks dry to me. try cleaning the petcock and rejetting. also back off to a BR9ES plug
Got The Holeshot
Arm chair racerJust too addicted
Bore the cylinder to whatever pistons specs you're using...in this case,Wiseco. .002 is too tight. Tapered bore ?? Find another shop. That's rediculous. It makes sense in theory but doesn't work in reality. Tight at the bottom and loose at the top?? Where was this .002 measurement taken at ?? Don't let it sit and idle any more than to warm it up. You need to put a varying load on it otherwise it will glaze the bore and the rings will not take a proper seat. You need to do a leak down test before you fire it up. Just because they replaced a seal doesn't mean it's not sucking air from somewhere else.
"You should never smoke in pajamas..
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Maybe you should return to Manaugua..
You could go un-noticed in such a place"
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At The Back Of The Pack
Arm chair racerAt the back of the pack
.002" is way too tight for an air-cooled 250, especially with a Wiseco in it.
That is where the problem lies.
Should be boring the cylinder straight. I never heard of using a tapered bore, but it's possible.
If the jetting in your carb is stock, it may need to be changed for that DG pipe.
Back to the top end though. I would go .0035-.004" on an air-cooled Wiseco.
They expand more than a cast piston, and differently also.
I learned the hard way on a '77 CR125M about the difference in water-cooled, and air-cooled bikes.
One piece at a time. Status: The Beast is Done..06-23-07
Back in the saddle again
Currently owned rides:
My sleds, and.........
1995 CBR600F3
1976 Kaw 400 triple-smoker......SOLD
1986 250R...owned since 1990
06-23-07........the R is finally done!!!
ESR pipe, Aktive reeds/CR cage, 38mm PWK, +4 Dominator
mild clean-up porting, an open K&N, CR and YZ calipers.......among other things
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Arm chair racerNew to the board
Thanks so much for the advice guys, it's absolutely amazing the incompetence I've managed to run across trying to get my damned bike running!
Does anyone know a good motorcycle machine shop that knows what they're doing in south florida? I'd be willing to drive up to Ft.Pierce or down to Ft. Lauderdale to get it done right once and for all.
Also, could I do a leak down test myself? I'd really rather not have to put that engine back in my bike once again, it was a *Edited**Edited**Edited**Edited**Edited* to get all the suspension back into place.
83' 250R
Always finding new and exciting ways to not give a hoot in hell
Catch me if you can
TDR (Tony Doukas Racing) http://www.tdrracing.com/tdrracing/index.htm just did the cylinder for my flat tracker and seem to have done a really nice job. If you send
Instructions for a leak down tester: http://macdizzy.com/leakdown.htm
Power User
Roostin Away
Man I haven't heard of TDR in ages, how big did they go on your R and for how much roughly? PM if you don't want o spread the details haha
Always finding new and exciting ways to not give a hoot in hell
Catch me if you can
Well I got special dealer pricing that I don't think I'm suppose to reveal, but the piston in it now is 68.5mm from a YZ250
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Arm chair racerNew to the board
I never ran a Wiseco that tight. In a water cooled motor I ran 5 thousandths and never had an issue. Let the cylinder get warm to the touch then ride it. 10 mins is way too long to let it idle. I thinkl your jetting is a bit lean. That tapered bore idea is not a good practice. Straight bores make power. Forged pistons need room to grow. With todays good oils 40:1 is fine. check and double check for any leaks spray WD 40 around areas to check. Seek and ye shall find!
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Oh crap, I just went to TDR's site thinking I was going to have to ship my cylinder off, you didn't mention they were in Pompano!TDR (Tony Doukas Racing) http://www.tdrracing.com/tdrracing/index.htm just did the cylinder for my flat tracker and seem to have done a really nice job. If you send
Instructions for a leak down tester: http://macdizzy.com/leakdown.htm
Thanks Billy
83' 250R
Just Too Addicted
Arm chair racerJust too addicted
I'm having the exact same problem with my 83' R. Its in pieces in the garage right now, not sure what to do.
1984 Honda 250R
1985 ATC 250SX
1985 Tri-Z 250
1983 Honda 250R
1986 Honda 350X
1983 Yamaha Tri-Moto 175
1983 Honda Big Red 200
1981 Honda ATC 110
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