Hey Vital, read my piston and spark plug

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3/2/2018 4:12 PM

I've just pulled the top end off my yz250 and I'm looking for some feedback on how it looks to be running.
I'm thinking it's running rich although it feels really good to ride and minimal smoke and no spooge from the exhaust.
Also looks like the rings are well past their use by hours.
Bike is completely stock except for dep standard length silencer, run around sea level with 40:1 silkolene comp 2 premix with 98 ron pump fuel, no ethanol.
I was thinking of dropping the needle one clip, would this work or should I switch out some brass as well?
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3/2/2018 5:11 PM

I am seeing signs of a leak in the crank shaft seal on the clutch side. The jetting may be ok with that much blowby on the rings and it will tend to show rich at that point.

Paw Paw

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3/2/2018 9:48 PM

Thanks for the reply. I sent the photos to my mechanic and he thinks it could be a loose primary drive gear nut. Also the cylinder looks glazed, going to get it honed and have him cheek it all out

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3/4/2018 1:04 PM

chump6784 wrote:

Thanks for the reply. I sent the photos to my mechanic and he thinks it could be a loose primary drive gear nut. Also the ...more

Haha, I think your mechanic is testing his comedy on you!

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