Low compression test '80 GS1000G

[Guest]

I did a compression test (C/V carbs off), and got 50-60 psi on all four cylinders. I didn't do a wet test because the gauge is borrowed and didn't want to gunk it up. I'm wondering if with the carbs off if it can give a false reading. The gauge came from Autozone, and I'm willing to get it dirty with oil and clean if nesasary to see if I need to re-ring. But wondering if anyone has any advice about such low pressure?

[Joblofromidaho]

With carbs off your getting maximum air to cylinders,redo test ,maybe use a different tester making sure o ring is good on threaded adapter and is snug in spark plug hole,do not over tighten,crank it with good battery at least five revolutions .If the same results occur it could be a bad head gasket or cam timing if someone's been in there before.A little history on bike could be helpful,Joe

[JayWB]

The wet test won't do anything to the compression gauge; you don't use that much oil.

A teaspoonful at most, or a quick squirt or two is all you need. If the numbers come up dramatically you've got bad rings. If the numbers don't change you've got either tight valves or a faulty compression gauge.

Having the carbs off for the test is ideal, you want nothing inhibiting airflow INTO the cylinders.

[tkent02]

Have you adjusted the valve clearances yet? There can be no compression if the valves are not closing. 50 - 60 psi would be about right for valves that are almost closing but not quite.
Aldo if the engine has been sitting for years it will read low, adjust the valves and run it a month or so, it will be good as new.

Oh, and one more thing, adjust the valves.

[2BRacing]

Has the bike been standing for a long time? Rings could be seized up if it has. If you can get it running well enough to ride it for some time, this will help to free rings up. Then re-test while engine is warm.