Crazy compression increase - Help!

Hi,

My bike is kinda grumpy with me after my trip, and while doing a compression test - dry then wet, the compression on the 3rd cylinder jumped up from 140 dry to 210 wet! I had to measure it 4 times before I believed it..

What the hell can cause that - is it a problem?? The spark plug in that cylinder is looking kinda rough too. Definitely a darker tan/rust colour than the other plugs, which are a nice light tan.

My timing seems fine too - I haven't checked valve clearance yet though.. At TDC my timing lines up nicely with the T, so it looks good so far. I don't think that I could get it to idle nicely right now, so I can't check it with a light just yet.. My main concern is that compression.

Halp please!

Well I would check the valve clearances oooooorrrrr it just could be the gap in the rings on the piston, seeing that they are supposed to be a certain distance apart. Hate to say a broken ring so I typed it. Good Luck!

What were the other cylinders? If you
put in too much oil the compression
will jump way up.

I did a compression test on my 750E recently, one squirt from my pump oil can was enough to double the compression from 100 to 200

Well, at least the valves are sealing good

The other ones went from 135/140/140 to 150/145/145..so pretty much bang-on.

I'll try it again tonight after letting the oil drain out a bit..maybe I did just put too much in.

So this isn't a big deal then..?

Are you checking the compression with the throttle wide open? Results are very different if you are not.

I am indeed..

One thing I failed to mention is that I lost a crapload of oil too.. I mean it was nearly dry. I think it's a gasket thing though, cause my head gasket has a leak..and a fairly substantial one from what I can tell, around the passageway for the oil to get up to the head cover.

Too much compression is never a problem until something breaks , knocks or gets a hole burned through it .

Maybe some of the oil leak is going into that CYL inside ?

Something to look into .

yeah.. I'm pulling the head cover off tonight to check valves. I loathe the idea of pulling the cylinders off though, cause that's a whole ball of wax I definitely don't want to get into..but if it needs it..I guess I might have to.

Can you use liquid gasket maker instead of a normal paper gasket on the valve cover - or do I need to order one?