YTM 225 DX low compression - 45psi

[jaykup]

I could not get my 225 to start, and knew I had fuel (thanks to Huffa's scan) and a new spark plug (nice blue spark), so I checked compression. I got 45psi compression when I did a test.

It was running fine a few days ago.

I'm thinking burnt valve.. seems too sudden to be a ring problem, there is no oil leaking from the cylinder/head/etc.

I'm in the process of tearing it down, just wanted your input.

Thanks

[freewheel3]

Squirt some oil into the cylinder via the spark plug hole and then recheck your compression. If its still 45 psi then its a valve, if its higher then its rings.
Remember to check your compression with the throttle wide open.