Hi, my 250 has not been running right. It starts first kick, good compression and lots of power above 5k, but at low rpms it feels like a 50cc, sounds muffled as well.

I have now checked the slowjet, reeds, adjusted the power valve, checked the muffler for blocks. Nothing has been unusual, still has no power. My next move is to check the power flaps for carbon build up, maybe they are not closing right? Any ideas from those who may have had a similar problem would be much appreciated....

when was your last top end? hows the plug look

air filter ?

what kind of bike are we talking about here. youll probably get more help and more specific advice if you tell us the year.

Thanks for the replies....Sorry it's an 03. Yeah the plug and filter are both new. As for the top end, piston was just done and has never been right since, I didn't do it though but the compression is good and like I said it has full normal power at high rpm. I was sure it must have been something obvious, but so far I'm stumped. Could it be some sort of electrical CPU thing? my power valve servo woks fine.

anyways thanks for anything you can offer.

edit: Maybe the plug is faulty somehow, I'll try swapping it out when I get home

Edited by tempoe, 17 May 2012 - 08:47 AM.

sounds like your pv is stuck open

Revisit the last thing you did, Piston facing the right direction?

tempoe, on 17 May 2012 - 08:44 AM, said:

its not the plug. definitely sounds power valve related. the servo works fine so thats good, and you said you adjusted the cables, are you sure they're adjusted properly and you can visually verify the valve is complete closing and opening as it should?

like terrobleone said, it sure sounds pv related.

AXAxiom, on 17 May 2012 - 05:44 PM, said:

i was thinking this, but i believe he would have issues throughout the whole rpm range. i dont know for a fact because ive never put a piston in to find out