Compression & leakdown test

[Bob Shaw]

I have a 82 GS850G with 56k on it. During my general tune up and valve check I usually do a compression check. The compression was low 115-130 PSI (supposed to range between 128-171). I'm not burning any oil,(no smoke out the exhaust) and I haven't lost any power. I checked with a local bike shop mechanic and he said he wouldn't worry about the low compression if I not seeing smoke out the exhaust he did suggest a leak down test. What is an acceptable psi loss in a leak down test. I did 1/2 ounce of oil in the cylinders and the compression raised 20 PSI. Any suggestions would be great. Thanks. Bob Shaw

[tom203]

No smoking,no increase in oil demand.- still plenty of power...... I'd skip worrying. My bike has about same mileage. I figure the valves will go first!

[Bob Shaw]

Thanks, I don't want to get into the engine if I don't have to..

[gustovh]

I have an 80 850L with 52,000 on it, not great compression but runs like a striped ape with little oil use. Run it as is.

V

[tkent02]

Have you adjusted the valve clearances yet? If not do it.

[Bob Shaw]

Thanks for your help.

[Buffalo Bill]

Well, who want's to open up an engine anyway? (DIYer stampede here)
Of course you've lost power, don't be ignorant.

[Rensdw]

Warm up the bike and then do a compression test, if you pour in oil you will screw up the test result.
Pouring in some oil is a way of testing worn piston rings, in your case: changing piston rings will probably help gain some power and compression back.

If you don't need/use the power leave it as is like all the others are saying here

[tkent02]

Did the compression come up after you adjusted the valve clearances?

[Bob Shaw]

Compression stayed the same. It only increased after I put half an ounce of oil in the cylinders. Rings may be worn but as I said I haven't lost power and I'm not burning oil. I'll leave it alone. Thanks again...