Hi, new to the forums. So I Installed a wiseco piston, bored correctly, installed correctly, all new gaskets, and torqued right. Yet it only makes 65psi? What could possibly cause this?

 

What is it?
2 stroke? Reeds broken, debris holding one open?

 

oh, sorry. Polaris trailblazer 250, 74mm, carb cleaned, new piston, fresh bore, new rings, gaskets. Yet to touch the crank seals. Thanks

 

Crank seals will affect how it runs, but not compression in my opinion. Carb is the same situation. If you only have 65 for compression, I'd tear it back down. Something is broken, cracked, or warped. Piston in backwards???

 

"I'd tear it back down." Yep.

 

it was all put together right, which is why I don't understand it. Head warped maybe?

 

try pouring a bit of 2-stroke oil in the cylinder, replace plug and crank it slowly...if oil seeps from the jug/head then bad gasket or machining...if you can crank it and no seepage then you have a piston/ring to cylinder clearance issue...

Hopefully you had the throttle wide open when checking the compression...