Electrical Nightmare - 1982 GS750T

[Redman]

I had same situation of no spark with plug laying on head, but did spark when held just off the head. But notice if the spark is jumping between the head and the base of the plug (not the center electrode), if so, then plug is bad. You can verify this by swapping plug with another and see that this symptom stays with the plug not the plug wire.

Or you can measure the resitance between the spark plug connection on top and the base (treaded area), should be very high, infinite or a several hundred kilo ohms. I suspect that on this suspect plug you described, you will find it to be only a couple hundred ohms or less. I dont know what happens to a plug to make it fail this way, but have had it happen twice now in last few years.

Or is plug all wet with gas? Dry it and the cyclinder out, and try again.

[denouden]

There is no polarity on the coils. Have you checked the plug caps?

For what? Cracks? Inserted firmly? Spark?

All four act the same way...and as far as I can tell, they are in good shape...

The bike ran fine until I tracked down the short and fixed it, now nothing...

I find it very odd that when I lay the plugs on the head (and I've tried moving them around)...no spark. When I "hover" them above the head...nice blue/white spark.

I've also tested the continuity of the wires coming from the ignitor. One is yellow/black, one is white. If I connect one test lead to white (on the ignitor side), I get infinity on both the white & black/yellow leads on the coils, and it's the same result the opposite way around...

This doesn't seem right to me...any thoughts?

[denouden]

I had same situation of no spark with plug laying on head, but did spark when held just off the head. But notice if the spark is jumping between the head and the base of the plug (not the center electrode), if so, then plug is bad. You can verify this by swapping plug with another and see that this symptom stays with the plug not the plug wire.

Or you can measure the resitance between the spark plug connection on top and the base (treaded area), should be very high, infinite or a several hundred kilo ohms. I suspect that on this suspect plug you described, you will find it to be only a couple hundred ohms or less. I dont know what happens to a plug to make it fail this way, but have had it happen twice now in last few years.

Or is plug all wet with gas? Dry it and the cyclinder out, and try again.

Drying the plugs is easy but drying the cylinder out? How would I do that...? The plug I pulled was a bit wet...

[earlfor]

Take the sparkplugs out and set them aside on your workbench.
Do NOT lput the sparkplugs back in the boots because its a handy place to let them hang.

Put some rags or towels over the top of the engine. With the bike on the centerstand and in neutral, spin the engine over with the starter. This will blow excess gas out the spark plug hole. It comes out with force and in a mist. That is why you want the spark plug holes covered and that is why you do not want a connected sparkplug that can turn your garage into a large combustion chamber.

Earl

Or is plug all wet with gas? Dry it and the cyclinder out, and try again.

Drying the plugs is easy but drying the cylinder out? How would I do that...? The plug I pulled was a bit wet...[/quote]

[denouden]

Thanks everyone for your help. Bought new plugs, threw them in and she fired right up and ran gooooood.

I'm all ready to go now, just have to wait for the snow to melt...hehe. Should only be another couple weeks.

Thanks again.