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09 yz250f smoking during acceleration


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Ok I have an 09 yz250f that has started puffing a little white smoke on acceleration. I had a buddy ride it with me behind him so I could see exactly what it was doing. It will smoke for about a second when accelerating while under a load. Basically when leaving a corner it will puff. The bike also has a little stumble up to 1/4 throttle. It is like it will hesitate ever so slightly then hits rather hard. I know its pretty hard to explain over the internet. I am a pretty mechanically inclined person, but am fairly new to dirtbikes. I have been told the smoke could be either rings not seated, or head gasket. I am doing the top end as soon as the parts come off back-order. The only thing I am wondering, is could a jetting issue cause this puff of smoke? The reason I am wondering that, is it didn't start doing it until I put in the JD jetting kit. I am still learning the ins and outs of jetting. The bike had a bog at the first snap of the throttle, and that is why I went with the JD kit. The bog got better and now I just have the slight hesitation. Here are my basic stats:

185 - main

42 - pilot(stock)

105 - pilot air jet(stock)

1.5 turns - air/fuel screw

1.5 turns - boyesen qs3 adjustable leak jet(#55)

JD kit blue needle 5th clip

also have done the o-ring mod using the thicker o-ring supplied in the JD kit

Dr.D stainless header/aluminum silencer

That should cover everything. I would greatly appreciate any help you could give. Basically I'm just trying to soak up some knowledge for the future. Thanks

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