compresion

[acmemetalfab]

i checked the cylinders on the gs750e i'm working on for compresion. the reading were:
#1, 135psi; #2, 114 psi; #3, 116 psi; #4, 126 psi

had to take the readings cold, the bike has the carbs off for now. anyhow, they aren't within 10% of each other. is this normal for these bikes?

[rgierer]

IMHO all that you learned is that your cylinders have some compression. Others will provide you with very fine instructions regarding how to properly test compression but it it almost impossible to gett an accurate reading without the carbs on.

You can rule out, pretty much, that you have a catastophic compression problem.

Hang in there.

RG

[Jethro]

I was always of the mindset that you could check compression just fine with the carbs removed from the bike.

What is your bike? I believe that with my 1100's the correct range is somewhere between 150 and 170, and that 20 psi difference is acceptable, but maybe it is a % thing, too lazy to dig out the manual.

Anyway, your compression may get better when warm, and they aren't too far apart, so I'd say compression is ok.

When was your last valve adjustment?

[mark]

I agree with above post, you can test O.K with the carbs off. Valve adjustment is important too. I'd say for an older bike, they aren't fabulous numbers, but you're good to go. You could add a little oil to your cylinders and see if you get better readings.