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Discussion Starter #1
What are the symptoms of too much compression? My manual says 120psi minimum with a maximum of 145psi. My test came back with 150psi with two different gauges. I do have a 1mm over piston. The atv currently smokes under full throttle.

Thanks


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I would say your compression is perfectly fine, which would mean you cylinder, compression rings and valve seats are in good shape. But this does not mean your oil control rings are not worn/cracked or your valve seals are in good shape.
When you installed the piston, did you replace the valve seals?
 

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Discussion Starter #3
Not this last time. They were replaced about 4 years ago.


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I would say your valve seals are leaking more than likely. The only way to know for sure is to pull the head. Since its off, might as well pull the cylinder and inspect the oil control rings.
 
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