I did some routine maintenance on the 82 GL1100 today, and did my first ever compression test.
Warmed the bike up, and got readings between 85 and 90 psi on all cylinders.
According to Clymer's manual, readings under 140 mean an engine overhaul is due.
My question is, how bad is 90 psi? How imminent is my overhaul?
I'm assuming from the burning oil at startup that I'll need new rings. I have not checked the valves yet (plan to do that this winter when I replace the valve cover gaskets and timing belts).
I haven't checked compression on my wife's V30 yet. But when I do, should I do it cold or warm? What threshold do you use when considering compression on a V4. What is too low for comfort?
how did you perform the compression test?
ReplyDeletedid you pull one spark plug at a time and test each cylinder, then put that
plug back and test the next one?? (the wrong way)
or
Did you pull ALL the spark plugs and test the compression with all the plugs removed? (the correct way)
How many crankshaft rotations did you crank the motor for each cylinder ??
You should have the throttle open (not necessarily
ReplyDeletewide open but not shut) and remember to ground the
spark plugs but don't position them anywhere near the
heads.
Engine should be at operating temp when compression
testing.
Well, based on your description, I did it incorrectly. I did pull one plug at a time.
ReplyDeleteI used the starter to turn the motor. I cranked it on each one until the guage stopped climbing, per the compression tester instructions. I did conduct the test with the bike at operating temperature.
Thanks for your help.
I bet you'll get better results when you redo the test with all plugs removed and the throttle open. However, the existing test results are already encouraging because they're consistent from one cylinder to the next. As for the smoke - if it happens at start and then goes away your rings are fine - what's happening is that oil is running down into the
ReplyDeleterocker covers and then seeping through old valve stem seals into your cylinders. When you start up that oil burns away and all is well. I wouldn't worry about it - you can minimize the oil burned on starting by habitually putting the bike on the center stand rather than leaning it over onto the side stand.