lost top end

[arjay]

Hi - I'm running a Doma rev pipe on my Husky 125 with vforce and standard jetting. The bike was running fine but has developed a top end sputter. Top end power gets pretty thin then starts to break up. I noticed that the pipe is very slightly out of line at the cylinder, with part of the o-ring just visible - not much though. Would this be the likely cause?

 

[Tugsy]

I had similiar problem with my 1994 RMX 250 when new fatty pipe was installed and I had to richen main jet.....I also would be concerned on the alignment issue but would maybe go with higher main jet (2 sizes) to see if there was any change.

 

[bud]

Hi - I'm running a Doma rev pipe on my Husky 125 with vforce and standard jetting. The bike was running fine but has developed a top end sputter. Top end power gets pretty thin then starts to break up. I noticed that the pipe is very slightly out of line at the cylinder, with part of the o-ring just visible - not much though. Would this be the likely cause?

Doubt it, there's 2 o rings.. If it started suddenly, I'd guess the power valve is stuck closed.

 

[arjay]

Thanks. The bike's been lying round for a a few months unused. I wheeled it out last weekend to race and found that there was a lot less resistance on the kickstart. I could have fired it up by hand. It started ok, sounded ok but wasn't running great. No bottom end at all - it was bogging all the time unless I slipped the clutch like crazy and got it into the mid/top end. I had jetted the main up a couple of sizes but it didn't stop the overrev misfire. I'm stripping it down tonight and hoping it's not a bank loan type of problem.

 

[cello]

Had the same problem with my 250 - turned out to be the PV stuck in mid way position.

 

[arjay]

The pv was ok. Turned out to be bore damage from a part seizure, running too lean sometime in the past. It's minimal but enough to lose compression. This could be the spur to get the 144 conversion...

 

[JWRFlame]

144 Conversion?

Is that a 144cc conversion? Who makes it? Cost Thanks

 

[arjay]

Eric Gorr - Forward Motion, costs around $450 incl boring, machining, porting and piston kit. Check out the link on the left of the page.