1979 GL1000 timeing Spocket question


Information and questions on GL1000 Goldwings (1975-1979)
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mholmes7979
Posts: 2
Joined: Sat May 03, 2014 11:31 am
Location: Houston, Texas
Motorcycle: 1979 GL1000 Goldwing

1979 GL1000 timeing Spocket question

Postby mholmes7979 » Sat May 03, 2014 1:00 pm



New to the user group so any help would be appreciated. I'd like to say that I am a fairly solid mechanic but, I'm not too familiar with Goldwing engines. I bought a 1779 GL1000 about a year ago. It ran just fine & did not smoke. I decided to do a basic service on the bike and found Cylinder 1, 2 & 4 had 150 LB while cylinder # 3 had only 90 LB's. I suspected a gauge problem & since it did not smoke just went ahead and started riding it. About 100 miles later I decided to check the timing belts and adjust the valves. I did change both belts and adjusted the valves. Recently I got a compression tester that I felt comfortable with and checked the compression again. Now the pistons that had 150 LB's have 90 & the # 3 piston which had 90 is down to 30 Lb's. I took both heads off and found there was no ring ridge and all piston walls looked like they still had cross honeing marks however the # 3 head has a bent intake valve. Sorry for all the detail but now to a concern & question. It bugged me as to why three cylinder has 150 LB compression & now 90 & why # 3 went from 90 LB to 30 LB (obviously due to bent intake vale but??). While looking over everything and turning over the engine to #1 TDC several times (before I took the heads off), I noticed the sprocket on the #1 & #3 head had a hand scribed timeing mark on it that was not in the same spot as the arrow and case mark. I found that if I put the sprocket where the arrow and case mark was that the #1 valve (forgot which one) was part open. If I set the sprocket to the hand scribed marks the #1 piston is at TDC and both vales are closed. I took off the sprocket from the cam and I can see that it can only go on one way. In addition the TDC mark on the flywheel has the #1 piston at TDC of its' travel. So, what's up here? Can one get the sprocket wheels reversed? One that is on #1 & # 3 head should be on #2 & #4 ? Any thoughts would be greatly appreciated.



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Fred Camper
Posts: 1152
Joined: Sun Aug 16, 2009 9:15 pm
Location: Metro Detroit, MI
Motorcycle: 1977 GL1000, 1976 LTD GL1000

Re: 1979 GL1000 timeing Spocket question

Postby Fred Camper » Sat May 03, 2014 1:45 pm

It sure sounds like the valve timing is off. Not sure about the sprockets being reversed but it sounds possible. They certainly should align correctly and since they do not something is wrong. You will need to replace that valve and may as well lap all of them since the heads are off and replace those head gaskets. But since the three were at 150 and the one at 90 with a bent valve, you have a very strong engine there. I do think you goofed up the valve timing when you replaced the belts most likely due to the goofy sprocket situation.

mholmes7979
Posts: 2
Joined: Sat May 03, 2014 11:31 am
Location: Houston, Texas
Motorcycle: 1979 GL1000 Goldwing

Re: 1979 GL1000 timeing Spocket question

Postby mholmes7979 » Sat May 03, 2014 2:05 pm

Yup. No doubt I goofed the valve timing and caused the drop in compression. Just trying to figure out what a fellow or two before me has done. Most important point is I don't want to bend another valve. I suspect the first person who did the engine overhaul put the mark on the sprocket. Next person timed the valves via the arrow mark just as I did and most likely caused the bent valve.


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