XT600E 120psi cylinder compression
 

Done a test today due to the engine cutting out under load and it's 30psi down.

What is a 30 psi drop likely to be?

Just valve clearances? I can't check because I've lost my feeler gauges. I'll buy a new set tomorrow.

A bent valve? I did drown the bike on a river crossing about 3 months before it started playing up, sucked water into the engine.

Piston Rings? It does use oil as every large bore single cylinder does, but it's not smoking.

Any other ideas?

Thanks for any advice.

Sounds like you have problems with the piston rings yes, and i cant agree on the oil consumptions..I never refill oil beetween oilchange.

I concur...

Hmm. Thanks for the input, even if it's not the answer I was hoping for. Interesting to hear that you guys don't use oil at all.

I'll start on the valves and see where I go.

Really didn't want to be looking at a strip and rebuild.

It was valve clearances thanks guys. They were really tight. Now adjusted and getting a cold compression test of 135 psi, so once the fuel tank is back on and I can do a test with a warm engine, it should be up near spec.

Øh, how could the valve clearence get tight suddenly? And why should the compression dissapear due to the tight valve, what happens in that case is that you burn them. Sounds strange to me.

Valves probably always been that way since before I bought the bike. I've never done a compression test on it before and this is the first time I've checked valve clearances on it.

Tight valves will hold one or more open even a few thou, will drop compression, running long like that also can burn them as stated and erode the seats. As long as it wasn't like that to long, maybe no harm done.
Sucking water in can also bend a valve, depending how much water and what rpm the motor was running at when ingestion occurred.

Oil consumption should have nothing to do with engine size or number of cylinders. Hour and mileage will , same with poor maintenance . Or in the case of my KLR, bad factory ring design.