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Fresh top end with first gear bog - Video link attached

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A 1994 KX125... This is my first 2-stroke (and a new purchase for me), i was told by the previous owner that the oil from the exhaust was a sign that it needed a new piston ring. Replaced the piston and ring and now the bike bogs down bad from a stop/very low speed while in first gear.

New piston and ring (Wiseco spec sized for the year but is flat while the original one was crowned)
Cleaned the carb (42 pilot jet with a 158 main jet) 800' above sea level
Reeds look great
Repacked the FMF silencer (still have oil out the exhaust so I know its running rich)

I just can't figure out what else to do or check. The bike has great pull and power in the upper RPM range of first and all through the rest of the gears it pulls strong. Just looking for something that I might be missing.

I have been searching this forum along with others for an answer to the issue I am having but have been unlucking in finding any leads...


Edited by _Ezeekial_
Left out the year and model
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doesnt sound that bad to me.  could have a worn clutch basket so it's not freely engaging/disengaging.  trying fiddling with the airscrew to see if you can make it better/worse.  if it gets better with the airscrew turned in try a bigger pilot.  make sure your floats are set properly as well.

also a good idea to let the bike warm up for a few minutes before ripping on it, esp with that forged piston in there.

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Oil on the silencer has nothing to do with the rings, and everything to do with jetting.

See the jetting guide on kdxrider, dirt rider, TT, out wherever you want to view it, and do it step by step.

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