Sweet. Thanks for the help guys, good to know 1000rr.net hasn't been lost to trolls and smart asses who try to chase the techs or guys with knowledge away...

 

Well in the manual I can't seem to find anywhere that it states any variation allowable. I believe from general automotive experience that about 10% is the max allowable variation between cylinders.

 

I'd imagine it's like an auto, as long as they're not too far off from one another....

i.e. if the whole engine has shitty compression, it'll still run "OK" but if 1 cylinder had high compression compared to the others.. etc.

whats your bikes actual?

 

Just did a compression test with my buddy's R1. Yamaha's service manual gives a range, something like 150-230. His results from all cylinders were pretty close to the 180-190 range. I think what you need to look at, is somewhat similar numbers from all cylinders, if one is significantly off, then you have an issue with blow by. My guess is that the number varies greatly per the tool you use as well, so unless you are in the 140-150 range, you are probably ok.

Are you trying to determine if you have the piston ring issue? I had that fixed on my bike.