Sporadic Igniter??

[Guest]

Last fall my 1979 GS850G starting losing power for several minutes at a time. I believe I've finally tracked it down to the igniter for 1, 4 cylinders. I see this now when starting it cold. These cylinders won't fire at all. After bike warms for a few minutes. They'll start firing. Occasionally, they'll quit firing when running. I've checked connections, they appear good. I put in after market electronic ignition a few years ago. I have igniters off of a 650. Would these work to test if I have a bad one? many thanks, Mark

[Carter Turk]

Switch coils from 2-3 onto 1-4, hopefully the plug wires are long enough. See if the problem moves to those cylinders.

[tom203]

.....I put in after market electronic ignition a few years ago. I have igniters off of a 650. Would these work to test if I have a bad one? many thanks, Mark

What kind of aftermarket ignition? The 650 ignitor was designed to work with its own special signal generators-might not like someone elses.

[Crankthat]

I had a coil go bad before.
It was intermittent also.

[bwringer]

I've seen one of the pickups for a Dyna ignition fail when it got warm.

We took the ignition cover off the bike and on a cool day it would run great as long as you wanted (plenty of cooling air). If we put the cover back on, it would fail within five minutes. The owner called Dyna and they replaced the bad part.


If it's a Dyna ignition (or most others) there's no separate "igniter" -- everything is contained in the pickup coils. On a '79 850G, you could temporarily convert back to points if you have a known good set.

In order to try an ignition from another model, you'll need the whole thing -- pickup coils and plate as well as the igniter. Some models also have a plate instead of the mechanical advancer.


But step back a moment -- you don't need to do all that. There are only two components here. You either have a bad coil or a bad pickup/ignition (assuming you have a Dyna or something similar).

Swap the coils and you'll soon know which -- if the problem moves to the 2-3 cylinders, it's a bad coil. If it stays with 1-4, then it's a bad ignition part.

Naturally, a bad or intermittent connection anywhere in the system can masquerade as a bad part.

[bjrpkr]

Thanks Mr. Turk. I tried this and weirdly, the bike wouldn't fire at all. I have coils off other bikes but assume ones from a 650 won't work on an 850? I tried one, it appeared to work, but weakly. I'm going to try some of the troubleshooting techniques on here for test coil or signal generator. The electronic ignition is only a few years old so I wouldn't suspect it. But who knows? thanks for your reply...Mark

[tom203]

"....but assume ones from a 650 won't work on an 850?"

coils are similar (ohm wise) but connections are different.


do some testing

http://members.dslextreme.com/users/storagecliff/images/electrical_odd-n-ends.html#A17

[chef1366]

I've also seen a few Dyna S go bad.
If you use an igniter you will need the signal generator, advance and crank trigger also for an 850. The 650 igniter will work with all the matching components.

[bjrpkr]

Thanks again to all you great commenters. I appreciate you taking the time to look. Nothing like a good trouble shooting lesson. I'll dig some instructions off of this forum and see what the issue is. I DO have the Dyna. It has been flawless. I do suspect the coil because I pulled the wires apart slightly while running and there is juice going to igniter. I'll still do a thorough ohm check.
Mark

[Carter Turk]

I've had one green 3.0 ohm coil go bad and one Dyna-S go bad. The Dyna-S was brand new, the 1-4 trigger was faulty. They took care of me, great customer service.