Odd (to me) spark issue

[LAB3]

Over the last week or so there's times when the bike just won't start. It cranks over good and all the lights seem to be working but it just won't start, then all of a sudden it will start and seems to run fine. Today it happened again and I started looking into things like cleaning up my grounds and battery connections. When I put a plug onto the #4 plug wire and crank the engine there's no spark but get this, as soon as I turn the key to the off position the plug fires. Any clue at where I should be looking?

[oldyam80sg]

I dont know if this will help but I had the connector from the starter button where it connects to come loose and eventually it wont start. Just a thought. I connected it and put shrink tubing over it. so it wont work itself loose.

[Radioguylogs]

Over the last week or so there's times when the bike just won't start. It cranks over good and all the lights seem to be working but it just won't start, then all of a sudden it will start and seems to run fine. Today it happened again and I started looking into things like cleaning up my grounds and battery connections. When I put a plug onto the #4 plug wire and crank the engine there's no spark but get this, as soon as I turn the key to the off position the plug fires. Any clue at where I should be looking?

You have a lot of knowledge and experience with your bike. I hate to insult you by asking if the #1 plug is attached to the #1 plug wire, and the threads of #1 and #4 plugs are both connected (usually touching the engine).

I think you know #1 and #4 must be connected in a series electrical path.

[bikerphil]

Check the 4 pin connector at the TCI. The terminals can become stretched and cause an intermittent connection to the P/U coils.

[DEEBS11]

LAB3, do you still have a ballast resistor on your coils?

[LAB3]

Thanks for the responses. I finally got around to doing a REAL replacement of my pickup coil wires instead of relying upon the roadside patches that have gotten my through. Pulled off the pickup coils and let the wiring harness loose so I could get to everything, used 18ga silicone wire from a hobby shop, plain uninsulated barrel crimps with a REAL wire crimping tool and shrink wrapped everything. Did that yesterday hoping that was the problem so it was after the problem started BUT I have loosened and retightened the pickup coils themselves so I'll check the gap to make sure it's reassembled properly.

Pulled the wires off the TCI to check and see if they where corroded or otherwise dirty, clean as a whistle! I'll look over those wires for stretching.

Radioguylogs I'm not sure I'm following your wording. All plug wires where connected when I checked the spark, I added a used plug to the end of the number four wire and grounded the electrode on the big nut at the top of the cylinder head when testing.

Yes, I still have my ballast resistor and it came to mind after posting this last night. Gonna need to warm up a bit this morning but I'm gonna check that first thing.

[LAB3]

The spark while turning off the key is still puzzling but at least I tracked down the problem, I'm losing 1.8v through the key switch as measured at the red/yellow wire at the fuse box. Gonna trace that back through the harness but my guess is it's the switch itself.

[DEEBS11]

LAB3, I'm sure you know, the key switch is serviceable. It can be taken apart and cleaned. Might do the trick.

[LAB3]

LAB3, I'm sure you know, the key switch is serviceable. It can be taken apart and cleaned. Might do the trick.

Yep it sure is and boy where those contacts dirty! After sorting that out everything is now working as it should.

[DEEBS11]

Awesome. Back to traveling.

[LAB3]

I've stayed put for going on two weeks now at a motorcycle oriented campground in northwest lower Michigan and will probably stay til the end of this week. Still getting frost at night and most places to camp are in the woods, they won't warm up much for a couple of more weeks. Being in a sunny spot with good cover from the prevailing wind is what you want in temps like this.

[skids]

There was specific information on the old site concerning spark when the key gets shut off. I remember that but I cant remember what caused it. A collapsing magnetic field or something...
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