yz426 Compression Problems

[Mudder1228]

Alright, so I pulled my bike out to get ready for some spring riding and couldn't get it to start.

I changed the spark plug, tested for spark and it was there. After checking it out with my buddies, we found out that it can be kicked fairly easily without the decompression being used.

Its not new enough to have auto decompression some at this point I'm stumped. The only thing I know to do is pull the engine out and check for a stuck valve, but not something I'm too excited about getting into.

Suggestions would be very helpful.

Thanks!

 

[mkelly04]

When is the last time you checked valve clearance?


I'm not that familiar with the 426, but does it have a manual cam chain tensioner? If so, are the cams still in time?

 

[Matt90GT]

check your valve clearances. If they check out, probably time to install a new piston and rings.