GL1200 engine miss

Information and questions on GL1200 Goldwings (1984-1987)
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Posts: 5
Joined: Thu Apr 24, 2014 7:18 am
Location: Bedford, KY
Motorcycle: 1984 GL1200A

GL1200 engine miss

Postby kywinger84 » Fri Sep 12, 2014 4:56 pm

Can't seem to find a solution for an engine miss. 138K, with 3K on carb overhaul, all new gaskets - O-rings - CV diaphragms - air cutoff valve - vacuum/fuel hoses - spark plugs - spark plug wires & caps – air & fuel filter – sync’d the carbs. Bike was running very strong.
While riding the engine started to miss and cleared after 15 miles. A week later the engine started missing again and will not clear up. The miss decreases under accelerating load and then comes back when leveling off at a constant speed. The engine seems to idle fine, starts to miss when opening the throttle to start moving.
Since the bike was performing so well I can’t pick a good starting point. Anyone have a good idea of where to start investigating.
I don’t see the coils being affected by opening the throttle.
Do the pulse generators fail catastrophically or flake out slowly.
Also, has anyone tried moving the pulse generators to the engine front of an 84 GL1200.

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Re: GL1200 engine miss

Postby WingAdmin » Mon Sep 15, 2014 8:29 am

I think you're right in targeting the pulse generators - and they can degrade gradually. I also do think it is spark related. The more load the engine is put under, the more spark is required to ignite the fuel/air mixture. A weak spark will run an easily loaded engine at low speeds with no problem, however under heavy acceleration or at high speeds where the engine load is increased, a weak spark will present itself as a miss, as you are experiencing.

Posts: 5
Joined: Thu Apr 24, 2014 7:18 am
Location: Bedford, KY
Motorcycle: 1984 GL1200A

Re: GL1200 engine miss

Postby kywinger84 » Fri Oct 10, 2014 9:29 am

Update on engine miss this might help someone else.

Checked coils ohm at 15k each, spark plug caps 5k each
pulse generators 1180 & 1080 ohms each, one is a little low so I will try to find some replacements.

Since it was easier to change out I replaced the ICU first and found this to be causing the engine miss.
Engine starts quicker on choke and comes to idle faster with choke off.
ICU had been failing slowly before engine lost fire to two cylinders.

Turning throttle off the bike coasts longer since all cylinders are firing and not popping from mufflers.

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