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I know that you're supposed to do the compression test with a warm engine. But being that mine won't run yet I got curious. With the kickstarter and throttle fully open I got 126 psi on the left cylinder and 121 on the right cylinder.

Is this decent?

Or is it completely meaningless being cold? i would assume it would rise some with a warm engine.
 

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you can do a compression test on a cold engine. I did a cold test on my 175 and a warm one and there was almost no difference in compression.

I pushed mine in first gear to turn the motor over a few times as an option. kick starting it can be a pain sometimes.
 

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warm you should be up around 160 or so. 125, with that difference, i think is probably ok cold. like, i wouldnt tear it down because of that. get it running then check it again. remember, throttle open too. the piston will expand warm, so it should seal a little better. i say its not worth tearing into for 125. if thats what youre asking.

jc
 

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quote:Originally posted by 56cbr600rr

then that means my compression sucks.
The cold test doesn't give you enough information to make that determination. What you need to do, as Joe says, is a warm compression test, followed by a leak-down test. That will give you much more info to work with.
A leak-down test may reveal many things, bad guides, rings, weak cylinders etc.


FR

BTW, don't EVEN ask me how I know.
 
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