No spark to 3/4 cylinders

[glcafeinmygarage]

Hello,
I'm new to this forum and a new owner of a 78 GL1000. Got her last year and ran great. Then had the 3/4 cylinders cut out while riding, then came back on, then quit again. Now 3/4 won't fire at all. Took the coils out and both cases were cracked. Borrowed a working set from my buddy and still have no spark to 3/4. The PO did put an electronic ignition in (can't see any indication of who made it).

Any thoughts would be appreciated. I am limited as far as electronic knowledge goes.

 

[joedrum]

Hmmm seems to me if the coils have been switched out and still no fire ...the culprit has to be the electronic ignition ...one side of that is bad ...like coils there’s one for the front cylinders and one for the back cylinders ......welcome to classic

 

[glcafeinmygarage]

Joe drum,
Thanks for getting back to me with your thoughts. How can I test the electronic ignition to see if one side has failed?

 

[joedrum]

hmmm ..that’s kind of hard to check easy ...pretty much when you switched coils and same thing was going on ...is the test ...I’m thinking you have a dyna ignition set up ..but we don’t know for sure a pic would let us know ...check where this ignition set up plugs into wiring harness and make sure the connections are both plugged in ...should be around the ignition side ..side cover ...

Could take all the plugs out so not to be in motor ...switch those ignition wires I was just talking and see if fire starts going to the 3and4 wires ..might need help doing that grounding plugs proper ..seems dynas have had a lot of failures going on in recent years ...I know I had my share of problems with them and I’m glad I don’t have to deal with them anymore ...if I was betting as of now I would bet your ignition on that side is bad ...

 

[desertrefugee]

Going through a quick and dirty timing ceremony would tell you pretty quickly if one side wasn't firing. Pretty much the same process for all of them.

 

[Ansimp]

You can test for resistance which is hard but the usual method is looking for an expressed voltage whilst cranking. (1-3 millivolts?)

 

[OldCrow]

Since the electronic ignition probably just triggers the coil i.e. the ECM replaces the points. I'd also check that the coils primary 12V source is good. You could have chaffed wiring or corrosion at a connector.
Yeah cracked coils is a bad thing, high voltage just flying about willy nilly.

 

[Tom_Charlton]

look for a bad connection to the coil that isn't firing. You swapped coils with no effect, so the problem is further up stream.

 

[oldman Tim]

Bringing back a 3 year old post.
In Feb. of this year 2022, I bought a beautiful 1978 GL1000. It had been sitting for
4 years, according to the seller. Seller did say he used to ride it. She only has 44,000 miles on the clock.
Problem is, no spark to cyclinders 3 and 4.
It has had new points and condensor, plugs and coils. Coils were from Goldwing Parts, so I'm certain they are the right ones.
Still no spark.
I had read, I believe on this forum, to check the ballist resistor by by-passing the resistor using a jumper wire. I did that and there still was no spark.
I've used contact cleaner to try and clean up the stop switch and the start button. I did this without removing the switchs, just shoved the straw in there and soaked everything down good.
It used to run some on all 4 cylinders but once the temp came up, it would lose the rear cylinders.
Any ideas?
I have almost twice what I paid for this bike in mechanic fees.
Darn gremlins have got me stumped and the vintage bike mechanic I took it to has beat his head against the wall trying to figure it out.
I was thinking of calling the local priest to wash the bike with Holy Water but for some reason, I don't think he'd do it.