Hi all
I have a kx250 with a pooly engine. The other day i had just started the bike letting it warm up when it fired a load of engine oil out of the exhaust and stopped runing. i have got the piston and rings out but they don't seem to have any damage to them is there any thing else that could have made this problem. hope you can help all thanks jon.

 

Send it back to Mr pooly for warranty!

Why would you pull the top end before a compression check?
What exhaust are you running and what other changes are with the motor?
What mix and with what are you using?
What plug are you running and is it, well...... it will be fouled now.
Just curious.

Welcome to KF