Compression Check Cold

Performed a compression check on a room temperature (105 F) kz750 and wanted to know what kind of figures I should be expecting. I know it says to warm the engine up first, but as this one is out of the bike I don't have much of a choice.

Thanks,
KC

takes at least 65lbs.of compression to create combustion.i have seen em run with less but not good and not for long.
a good runner should have at least 100lbs and a stout engine should be around 130-140.
hth

leon holmes

Ok, in the coditions above I check and found one cylinder was around 15psi, the others were 50-70. Added oil to the low one and got it to about 120psi. Figure rings and seals if I go this route then. I just wanted to see what range to expect with a cold compression test.

I see 145psi on all four cylinders on a cold engine with WOT

KawiConvert wrote:

Performed a compression check on a room temperature (105 F) kz750 and wanted to know what kind of figures I should be expecting. I know it says to warm the engine up first, but as this one is out of the bike I don't have much of a choice.

Thanks,
KC

I think the cold reading should be not more than maybe 30 psi lower than nominal (hot) reading.

Thats what I was afraid of. Time to keep looking or invest some money in a possibly shot engine.