‘78 Low Compression

Discuss everything about Honda GoldWing. Feel free to ask any question related to GoldWing.

Moderators: CYBORG, Oldewing, robin1731, Forum Moderators

Post Reply
MattMcCoy
Chrome Member
Chrome Member
Posts: 166
Joined: Fri Sep 11, 2020 7:12 pm
Location: Fort Worth, TX, United States

‘78 Low Compression

#1

Post by MattMcCoy »

Hey everybody,

There’s a handsome ‘78 in my garage that would be happier on the road, so I’m starting to take a closer look at the bike. It has 60 psi on #1 and reads 175 psi on the rest. I checked valve clearance, which is to spec, so I shot a bunch of PB Blaster into the cylinder. Compression went up and a leak-down test at TDC shows no escaping air (probably due to the penetrating oil)—seems air tight. My amateur diagnosis is that the valves/seats and head gasket both passed, so I’m looking at a ring issue—hopefully just embedded.

I plan to let the penetrant do its magic for a couple days and then try another compression test. If it’s still low, perhaps run it a little to try to free the rings?

Thanks.
1983 GL1100A Aspencade
1977 GL1000
1978 GL1000
1979 GL1000

“I see Angels on Ariels in leather and chrome,
Swoopin' down from Heaven to carry me home."
User avatar
77Gowing
True Blue Steel Biker
True Blue Steel Biker
Posts: 2724
Joined: Wed Jul 22, 2015 4:31 pm
Location: San Angelo, Texas

Re: ‘78 Low Compression

#2

Post by 77Gowing »

Matt, if the bike sat a fair amount then I think you are on the right track about the rings might be hung up on that one cyclinder. I have seen low compression cyclinders on an 84 increase by just running the engine. One of our venerable gurus even suggested I run the 84 a couple hundred miles and then retest. Anyway, the more I ran it the better she ran. When I first started On the low compression cylinders (two), I pulled the ign wire and got almost no change. After several hrs running stationary an ign wire pull started to make a difference so I noticed the cylinders were freeing up. I really should have rechecked the compression.
Anyway imho it started running better.
Our Polish friend has the bike now.

Id get her out on the road for a couple hundred and then retest compression. These engines have been known to go for many thousands of miles if well cared for.
"Less is More" Anonymous

77Gowing
1977 GL1000 "O'le Blue." (sold :crying)
2014 Yamaha 950 V Star (sold)
2017 Indian Scout Std w/ABS (sold)
2009 Honda VTX1300R "Me Brudder's" (sold)
1984 Honda Interstate "84' 2outa4." Gone
1982 Honda GL1100 "After thought." Gone
User avatar
Whiskerfish
President
President
Posts: 36853
Joined: Thu Feb 16, 2006 9:34 pm
My Album: http://www.ngwclub.com/gallery/v/wingmans/whiskerfish/
Location: Norfolk Va

Re: ‘78 Low Compression

#3

Post by Whiskerfish »

If you can exercise it with the starter and the plugs removed to see if there is any indications of improvement that might be worth the effort. Just make sure to observe a cool down cycle for the starter. Like 30 seconds on then 3-5 minutes off. These starters do not like to be over heated.

If you plan to keep it personally I would pop the heads off and take a look. Bikes that have sat have a much higher head gasket failure rate than others it seems. Any bike I plan to keep would get new head gaskets a lap job and new valve stems. About 200 in OEM parts but worth the investment plus you get to check out that cylinder wall for any serious issues before you invest a bunch or time and money.
"Agreement is not a requirement for Respect" CDR Michael Smith USN (Ret) 2017
"The book is wrong, this whole Conclusion is Fallacious" River Tam
2008 GL1800 IIIA "TH3DOG"
1975/6/7/8/9 Arthur Fulmer Dressed Road bike
1975 Naked Noisy and Nasty in town bike
and a whole garage full of possibilities!!

Psst. oh and by the way CHANGE YOUR BELTS!!!!
Shadowjack
Silver Member
Silver Member
Posts: 654
Joined: Fri May 26, 2017 11:07 am

Re: ‘78 Low Compression

#4

Post by Shadowjack »

+1 on running it for a while before worrying about compression figures.
MattMcCoy
Chrome Member
Chrome Member
Posts: 166
Joined: Fri Sep 11, 2020 7:12 pm
Location: Fort Worth, TX, United States

Re: ‘78 Low Compression

#5

Post by MattMcCoy »

Thanks for the advice. I’ve been soaking the rings with PB Blaster and working it with the starter once a day, as suggested. After evacuating the cylinder, I got a repeatable reading of ~90 psi, for an increase of about 30 psi. That seems to be encouraging. I’ll dump the old oil and try to fire it up this evening.
1983 GL1100A Aspencade
1977 GL1000
1978 GL1000
1979 GL1000

“I see Angels on Ariels in leather and chrome,
Swoopin' down from Heaven to carry me home."
low-side
Silver Member
Silver Member
Posts: 569
Joined: Fri Aug 04, 2017 5:00 pm
Location: Canton, Ohio

Re: ‘78 Low Compression

#6

Post by low-side »

Using this process can help free things up too: https://www.randakksblog.com/starting-a ... ng-lay-up/.
MattMcCoy
Chrome Member
Chrome Member
Posts: 166
Joined: Fri Sep 11, 2020 7:12 pm
Location: Fort Worth, TX, United States

Re: ‘78 Low Compression

#7

Post by MattMcCoy »

Thanks, low-side. I was lucky enough to stumble across that blog and used this method on two prior bikes with success. I enjoy the old-school process and the results have been really positive. Appreciate the advice.
1983 GL1100A Aspencade
1977 GL1000
1978 GL1000
1979 GL1000

“I see Angels on Ariels in leather and chrome,
Swoopin' down from Heaven to carry me home."
MattMcCoy
Chrome Member
Chrome Member
Posts: 166
Joined: Fri Sep 11, 2020 7:12 pm
Location: Fort Worth, TX, United States

Re: ‘78 Low Compression

#8

Post by MattMcCoy »

The bike started right up. It was cool to get a soundcheck on the turndown exhaust, although I’m not certain my neighbors would agree. Lots of smoke and occasional popping out the right side.

I’ll put fresh coolant, change belts, adjust valve clearance to 0.006, and then proceed through the Randakk method to see if I can get that compression up.
1983 GL1100A Aspencade
1977 GL1000
1978 GL1000
1979 GL1000

“I see Angels on Ariels in leather and chrome,
Swoopin' down from Heaven to carry me home."
MattMcCoy
Chrome Member
Chrome Member
Posts: 166
Joined: Fri Sep 11, 2020 7:12 pm
Location: Fort Worth, TX, United States

Re: ‘78 Low Compression

#9

Post by MattMcCoy »

Hey everybody,

I haven’t had much spare time, but wanted to start thinking ahead and get some advice while I continue on the engine. This bike has what appears to be a ‘79 front master cylinder with a slightly bulging rectangular reservoir. I would like to replace it with a ‘78, or upgraded master cylinder that maintains the same round look. I read back through years of guidance, but wondered if anyone had any thoughts or suggestions. I already have new black SS brake lines and pistons ready to rebuild the brake system.

Thanks.
1983 GL1100A Aspencade
1977 GL1000
1978 GL1000
1979 GL1000

“I see Angels on Ariels in leather and chrome,
Swoopin' down from Heaven to carry me home."
Figor
Cast Iron Member
Cast Iron Member
Posts: 96
Joined: Fri Jun 18, 2021 7:11 pm
Location: Central Illinois

Re: ‘78 Low Compression

#10

Post by Figor »

I fought that rectangular one for a few weeks and finally caved. I ended up buying a unit off Amazon that had some feedback from goldwing owners. So far I’m impressed. It stops the bike pretty good and doesn’t lock up the front very easlily so that is a good thing for the way I use it. I bought the set so it came with clutch lever assembly. It also came with a rebuild kit. Can’t be beat for the price of $27. Time will tell how it holds up.
1981 Goldwing GL1100
Microsquirt efi
User avatar
Whiskerfish
President
President
Posts: 36853
Joined: Thu Feb 16, 2006 9:34 pm
My Album: http://www.ngwclub.com/gallery/v/wingmans/whiskerfish/
Location: Norfolk Va

Re: ‘78 Low Compression

#11

Post by Whiskerfish »

Actually have read several folks here giving that $27 unit good reviews.
"Agreement is not a requirement for Respect" CDR Michael Smith USN (Ret) 2017
"The book is wrong, this whole Conclusion is Fallacious" River Tam
2008 GL1800 IIIA "TH3DOG"
1975/6/7/8/9 Arthur Fulmer Dressed Road bike
1975 Naked Noisy and Nasty in town bike
and a whole garage full of possibilities!!

Psst. oh and by the way CHANGE YOUR BELTS!!!!
User avatar
Oldewing
Secretary
Secretary
Posts: 8177
Joined: Wed Jun 08, 2005 8:19 pm
Location: Gahanna Ohio

Re: ‘78 Low Compression

#12

Post by Oldewing »

I have one on my 1100 with years of use on it, and have put them on countless other bikes since with no problems. I have a shelf full of the rebuild kits that come with them...

for the price, I would just toss and replace, but have not had a failure as yet...

that ought to open a door, eh?
82 GL1100 Interstate-Oldewing October 23 BOTM
06 GL1800 Road bike, as in Rode alot...
Sometimes I wrestle with my inner demons.........
Other times we just hug.......

Team 898
Team LTD 993
Team 76 R2B3
And always remember: beer has some food value--but food has NO beer value...
Post Reply
  • Similar Topics
    Replies
    Views
    Last post

Return to “GoldWing Tech Discussions”