Something a miss on my YFZ..

[redlineranger]

alright i dont know what it is. it will run good in all gears, until u get past half throttle, or once the revs get up a little bit. it just starts missing and bogging. every now and then it will rev high like its bouncing off the limiter. one thing is for sure it does not have the power its supposed to have. cleaned the air filter and air box out good, and changed the plug(which was pretty damn bad). but that didnt fix it. i wondering if i have a bent valve or if a valve is stuck or what. my friends 400ex was doing almost exactly the same thing one time and it wound up being a stuck valve.

anyone ever had this problem? some input on other things you think it could be would be appreciated.

thanks

[NacsMXer]

Is it pretty much stock? From what you say sounds like the main jet is too rich or plain fell out.

[bwamos]

Originally posted by NacsMXer
Is it pretty much stock? From what you say sounds like the main jet is too rich or plain fell out.

My same thought. Sounds like the mainjet wiggled loose.

[svahle]

Do you have a resistor kit? If so, are your lights unhooked? When I tried to run both lights and the resistor kit I had the same symptons. If not, I would check the main jet as mentioned above.