help needed low compression

[Anonymous]

On my gs 750 1979, i have low compression, approx 5bar on each cylinder compared to 9 when its new, doent use any oil so i dont thonk its the pistonring or pistons did airpressue test and no air came out. so the valves seem okay, So suggestions/ ideas will be apriciated.

 

[Anonymous]

5 psi? or 50?

 

[Anonymous]

Zamra;
I had the same question...5 what??

Also, pressure tests need to be conducted when the bike is warmed up...operating temp. Make sure it's not a cold engine your testing.

 

[Anonymous]

5 bar compared to 9 bar when it was new----
i have always been told that compression test should be done with a cold engine-the test was done at mc garage- the mechanic --like me suspected either the valves or worn down pistonrings- but the test didnt indicate any of these- we have a wage idea that the valves need to be adjusted -- any ideas or suggestions will be appriciated

 

[Anonymous]

Here in the U.S. we consider a bar as a place to get a Bud Light and be humiliated by women. Hell man, you know we just started using millimeters and centimeters for god's sake, and now you want us translate BAR. Next you'll want us to learn another language like Danish or something. Or how about giving up our AK47s and actually taking responsiblity for our actions.
Sorry, think I got a little carried away.

Back to the subject. Engine should be warm for compression test and throttle should be held full open.

Oh, by the way, many Americans are very familar with metric weight measurements like kilos and grams.
Axel

 

[mcycle-nut]

If kg/cm2 is the same as BAR, according to an old tire pressure gauge I have, 5 BAR equals about 72 psi, and 9 BAR is about 128 psi. And Axel, of course you're being humiliated by women, you're drinking Bud Light! Try Tuborg, it's a good Danish beer. 8)

 

[Anonymous]

First of all. i think youre right 5 bar is about 75 psi.
But isnt it possible to get serious advice from someone instead of just nonsens about bar or psi.

 

[gs650gt]

First of all. i think youre right 5 bar is about 75 psi.
But isnt it possible to get serious advice from someone instead of just nonsens about bar or psi.

he he...

ok, back to business.. according to http://ezwebz.com/gs-classic/ the compression should be 8 - 12 kg/cm2 (service limit 7 kg/cm2). And that's about the same in BARs. and the readings should be taken from a warm engine.

It's the valve clearances that must be taken from a cold engine!

 

[Anonymous]

if i knew about bar readings i would have givin you the answer, the answers arent non sense there just good questions.

 

[Anonymous]

Are these figures consistent across all 4 cylinders? Tried doing test when hot? Throttle wide open doing test? Battery charged well? Does a shot of oil boost these figures? How many miles on this engine? Adjusting the valves should be done first to get a proper reading. Bob