1980 GL1100 not running right


Information and questions on GL1100 Goldwings (1980-1983)
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manynails
Posts: 2
Joined: Tue Feb 26, 2013 8:52 pm
Location: Porthill, ID
Motorcycle: 1980 GL1100 Standard

1980 GL1100 not running right

Postby manynails » Tue Feb 26, 2013 9:30 pm



Hi all, I am new to the forum and in desperate need of help.
I bought a 1980 GL1100 for a winter project hoping to have it ready for spring but it is turning out to be a nightmare. It will not idle after it warms up, and backfires out the carb and exhaust.
I have checked the compression (OK), had the carbs rebuilt twice (including new idle air cutoffs), replaced the coils, checked the pulse generator and vacuum advance, changed sparkplug wires, checked the timing with a timing light (OK) and verified that the advance is working and tonight I did a cylinder leak down test (all cylinders OK).
But...
When I tried to sync the carbs the manometers do not show a reading, unless I rev it up then I get a slight reading. I stuck a vacuum gauge on one cylinder at a time and it only reads between 2 and 3 inches of vacuum per cylinder, every other bike I have done is usually around 8-10.

Is it possible to have a large vacuum leak that effects the entire bank or carbs (I disconnected the vacuum line to the advance and plugged it) or am I looking at an engine problem such as bad valve springs.

Even though I have good and even compression I was curious and while the cylinder was on top dead center I tried to put a vacuum on the cylinder (with a hand vacuum pump) and I could not get a reading. I then removed the boot from the carb to the cylinder and covered the intake port with a rubber glove. This time I got a bit of a reading on the vacuum gauge and it was sucking down on the glove (leaking past the intake valve which should have been sealed). I'm not sure if that is a valid test and means anything...just thought it was weird.

Thanks in advance for any and all help.

Jason



User avatar
littlebeaver
Posts: 4420
Joined: Mon Sep 21, 2009 6:11 pm
Location: Kansas City, Kansas
Motorcycle: 1981 gl 1100 I , 79 Yamaha XS11
Special, 82 Kawa 750 CSR, 82 Kawa 750 LTD, 03 Kawa Nomad 1500, 99 Kawa Voyager 1200

Re: 1980 GL1100 not running right

Postby littlebeaver » Tue Feb 26, 2013 10:08 pm

Hello Jason...welcome to the site, someone should be along to help you shortly... :D

User avatar
RoadRogue
Posts: 1917
Joined: Sun Jun 06, 2010 10:51 pm
Location: Castlegar BC, Canada
Motorcycle: 1997 1500SE

Re: 1980 GL1100 not running right

Postby RoadRogue » Tue Feb 26, 2013 11:34 pm

When you say the compression was good all cylinders , what were the numbers? Have you checked the valve clearences? Do you have a broken valve spring? Have you checked the timing belts to see if they are correct?
To me good compression but weak vacumm points to broken valve springs. 8-)
Ride safe, Todd
Over night campers welcome

manynails
Posts: 2
Joined: Tue Feb 26, 2013 8:52 pm
Location: Porthill, ID
Motorcycle: 1980 GL1100 Standard

Re: 1980 GL1100 not running right

Postby manynails » Wed Feb 27, 2013 10:26 pm

Thanks RoadRogue for the response.

I did check the valves and the belts (including the tension), there were no broken valve springs.

I double checked the compression today and was getting 135-140 (which is the bottom end of the spec)...BUT...I think it might be a problem with my gauge. I borrowed a couple other gauges and they read between 105-110, which is well out of service. I performed a wet test and the numbers did not improve so it looks like I will be pulling the heads.

Thanks again,
Jason




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