GL1000 Compression


Information and questions on GL1000 Goldwings (1975-1979)
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Solina Dave
Posts: 414
Joined: Fri Dec 26, 2014 6:38 pm
Location: Solina, Ontario, Canada
Motorcycle: 1978 Honda Goldwing GL1000 (bought in fall of '77)
!977 Honda CB550F (my 1st motorcycle)

GL1000 Compression

Postby Solina Dave » Fri Aug 14, 2015 9:50 pm



Just a quick question regarding engine compression. The Honda service manual says normal compression should be 171 psi. Anything over 199 psi. the engine needs work. Anything below 142 psi., or any variation of compression between cylinders of 15 psi. or more, the engine needs work.
The readings on my '78 GL1000, with all the plugs out, and the choke and throttle wide open, are 150,150,150, and 142. The motorcycle runs very well, and very strong. The compression check was done with a high quality gauge, and just out of curiosity.
If you had readings like this on your GL1000, what would be your analysis? Would you be happy, sad, concerned, very concerned, flippin' out and tearing into a full-on engine rebuild? Just wonderin'!

Thanks...............................Dave


"Assume Nothing"

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Aussie81Interstate
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Joined: Thu Nov 27, 2014 2:34 am
Location: Penrith Australia
Motorcycle: 1982 CX500 Turbo (restoration project)
1981 GL1100 Interstate (sold)
1988 GL1500

Re: GL1000 Compression

Postby Aussie81Interstate » Fri Aug 14, 2015 10:18 pm

My analysis would be - perfectly fine - and keep riding it. The cylinder with the slightly lower compression - could well be a valve adjustment.

Did you do a valve adjustment before doing the compression test?

I would also run a "wet" test to confirm if there are any further issues with that particular cylinder reading ( a spoonful of oil down the spark plug hole)..

User avatar
Solina Dave
Posts: 414
Joined: Fri Dec 26, 2014 6:38 pm
Location: Solina, Ontario, Canada
Motorcycle: 1978 Honda Goldwing GL1000 (bought in fall of '77)
!977 Honda CB550F (my 1st motorcycle)

Re: GL1000 Compression

Postby Solina Dave » Fri Aug 14, 2015 10:43 pm

Aussie81Interstate wrote:My analysis would be - perfectly fine - and keep riding it. The cylinder with the slightly lower compression - could well be a valve adjustment.

Did you do a valve adjustment before doing the compression test?

I would also run a "wet" test to confirm if there are any further issues with that particular cylinder reading ( a spoonful of oil down the spark plug hole)..


Yes, the valves were adjusted prior to the test. I'm not too concerned, just curious for input, I'll definitely keep riding, and I may give it a "wet" test as you suggest. That would add a little more to the equation. The engines got about 175.000 kms. since it had a ring job and a valve job.
"Assume Nothing"


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