Compression test


Information and questions on GL1100 Goldwings (1980-1983)
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shehawken
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Motorcycle: 1981 GL1100

Compression test

Postby shehawken » Wed May 16, 2012 7:53 am



I've been reading a lot about the compression tests. I'm pretty sure I have a stuck (and probably now bent) valve but I haven't been able to do the compression test yet. The dry test seems fairly simple (I'll have to doublecheck what I'm turning by hand) but the wet test with oil? What do you do with the oil after the test? Will it go out through the exhaust valve or should I be looking to get it back out of the cylinder somehow? Also, what's this I keep reading about sea foam for loosening things up? I'm guessing if I go that route I'll have to drop the oil and filter and then replace those? I'm trying to compile a list of things because most of this will have to be checked over a long weekend (and maybe repaired over a long period of time).



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RBGERSON
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had every year from 75 to 83

Re: Compression test

Postby RBGERSON » Wed May 16, 2012 8:00 am

First turn The. ending over by hand..if you can't do a full revolution you do have a valve hanging and it could hole a piston..if you crank the engine over..so don't do it if you can't turn by hand. The oil will burn off don't worry about it. But the oil test is just to see if the rings re the issue. Sea foam is more for cleaning out carbs..Stuck valves I'd use Blaster, or silicone solvent or similar solvent.
HAD LOTS OF GOLDWING 75-83
NOW INTO 1500'S..RIDING A 1998 SE

FAIR WINDS,
RB

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WingAdmin
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Re: Compression test

Postby WingAdmin » Wed May 16, 2012 10:09 am

Don't go pumping so much oil in there that it hydrolocks the cylinder, that can do lots of damage. Just enough to coat the surfaces of the cylinder wall - the idea is that you want it to seal the piston rings to the cylinder walls. If that doesn't raise the compression, then you know the problem is valves, not rings.

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Johnyy Smoke
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Re: Compression test

Postby Johnyy Smoke » Wed May 16, 2012 6:32 pm

Turn it over by hand first-the diy article on changing the timing belts expains how to do this-so you will know what to turn.If you can turn it over by hand-with NO resitance or pinging noise-then do the compression check.After you do the compression check on each cylnder ,then you can squirt (one little squirt) of oil into the cylinder you are hooked up to -to see if the compression improves.Remember to kill ignition-with throttle open during the check.Take your time and do the research on the web-read the diy articles here.Regards,Johnyy

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shehawken
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Re: Compression test

Postby shehawken » Thu May 17, 2012 8:53 am

Thanks for the advice! I should probably point out that I figured out something might be stuck when, the last time I started it, the engine turned over a couple of times and then made a sound like someone striking the engine casing with a hammer. I fear for my pistons... and my possibility of riding this summer.

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thrasherg
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Re: Compression test

Postby thrasherg » Thu May 17, 2012 3:48 pm

If you heard a bang, you might want to check your timing belts, if one of them broke, it would lock the engine up and damage the valve train.. Might give you an idea as to which side of your engine has the problem..

Gary

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shehawken
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Re: Compression test

Postby shehawken » Sat May 26, 2012 12:54 pm

Actually, the timing belts are brand new and still appear undamaged (I managed to yank the cover and inspect them- putting the gasket back in was not fun). I'd had the bike running since they'd been replaced (including the hour ride home from the shop) so I think the timing was at least originally right.

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seabee_
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Re: Compression test

Postby seabee_ » Sun May 27, 2012 12:33 am

Like the others said, turn the motor over by hand a couple of full revolutions to make sure nothing is binding. Then when you do the compression test make sure the battery is fully charged. Hit the kill switch and crank the engine with the throttle(butterflies) fully open, and all spark plugs out. Do a dry test on the cylinder first then put a couple squirts of oil in the cylinder and do it again. Repeat for the other cylinders and post back.
Paul
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shehawken
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Re: Compression test

Postby shehawken » Mon Sep 17, 2012 10:44 am

I didn't just disappear... I actually haven't had time to work on the bike (house repairs, second child) and have burned another season... Someone mentioned an article on replacing the timing belts which could help me on turning the engine over by hand. But I checked the articles in the DIY section for the 1100 and it appears this article has been removed. Any thoughts where to look? Thanks.

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eklimek
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Re: Compression test

Postby eklimek » Mon Sep 17, 2012 12:09 pm

Try this off site. Also search this site. There is a cute trick littlt beaver posted last year.

http://www.goldwingfacts.com/forums/forum9/17422.html




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