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YZ125 problem

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My sons 2004 YZ125 studders at the top end and seems to have little to no powerband. We rode last weekend and it was fine at the begining of the day and by the end of the day it started. I have changed the plug,cleaned the carb and reeds,checked the pipe and silencer for restrictions, checked the powervalve operation,air filter is clean. I cant quite place the problem, it seems that if you keep an even throttle it raps out fine but if you hammer the throttle... no power and studders. We just got this bike new from a dealer(but used 2004) about a month or so ago and had enough power that I pull wheelies with it,but not now. Seems like its getting 70% of what it should be.

I do know that the floats seem set high as it drips fuel at the slightest lean angle and I will set that tonite but Im not sure that has anything to do with the runnability.

any ideas guys?

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I do know that the floats seem set high as it drips fuel at the slightest lean angle and I will set that tonite but Im not sure that has anything to do with the runnability.

any ideas guys?

that might be it. if your bowl is overfilling it might cause a overly rich condition. if its just a little bit it might react fine under prolonged throttle and high revs, but when you hammer on the throttle it might kinda bog or stutter.

probably a good place to start

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Sounds like a weak ignition to me.

Thats kinda what I was thinking but I'll start with the float setting first and check spark energy after.

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Look for a leak in the exhaust somewhere or a bad plug cap or short in the kill button maybe. Also try fresh gas after you drained out the carb. One last thing to try............place the choke on about 1/2 notch as see what that does. IF it runs better w/ the choke then it's a carb issue.

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