Hey everyone, so I replaced my old, arching spark plug wires today with an aftermarket set, and upon removing my old wires, I discovered there was a very small gauge wire attached to the front cylinder wire. It comes out of the main wire harness for the coil (just before those wires enter the coil) and taps into the upper boot of said spark wire. There is a second small gauge wire that enters the coil itself.

My wiring guide doesn't show anything like this to be present (at least the wire that tapped into the spark plug wire isn't on my diagram). I put the new wires on and left the tiny wire unattached for now, and the bike starts up and idles just like normal, no idiot lights come on, and everything seems to be in good working order. Testing the odd wire, there is no charge in the small wire with the bike running or off (ignition on, engine not running) I haven't had a chance to test the other wire that taps into the coil yet.

Any ideas on what this could be? There isn't any aftermarket electronics or accessories on my bike, no alarm either. If it doesn't effect the bike or its not important, ill just probably eliminate the wires and be done.

(also, the old spark wires had steel braided covers, could that be relevant, like maybe they were a ground in case the wire went bad?)

I'm not electrically savvy, so forgive me if this a obvious answer lol

This is on a 1996 Sporty 1200s

 

Steel braided wire sets on high performance cars had ground straps on them. I installed a steel braided spark plug wire set on my old corvette years ago, it came with a wire loom for all the wires to run through. The wire loom had a small ground wire. At first I did not connect the ground wire. After getting shocked by touching the plug wires with the car running I connected the ground wire, no more getting shocked.

 

What color is the wire(can't tell in the photo)?
I don't think that wiring schematic in your pic is for a sport... all the 1200S schematics I've seen show 4 spark plugs, but I really think that's beside the point.
Judging by the angle of the coil boot in the photo it looks like the spark plug lead is out the rear of the coil (hard to really tell with that huge chrome coil cover)... all the 1200S coils I've seen have side exiting spark plug leads. 2 on each side, but I really think that's beside the point.

California models had a 'trap door' solenoid ...for emissions (I think)... its wired in series with the coil, start switch and emergency stop switch with a white/black wire.
More than likely it's a 'not in service' factory wire (with the black ground, the green starter relay and the 3 position deutch connector MIA), or... a no longer needed customer added wire (maybe for an after market tach).

Somebody may have stuck it into the top of the sp boot to keep it out of the way.

 

Check the continuity of the wire back to ground with the key in the off position. This could confirm the wire shield ground theory.

 

What color is this 'other' wire?

 

It`s probably for a tacho, it only needs to be in close proximity to the spark plug lead to trigger a signal for a rev counter

 

That's what I thought at first, however the tach still works with the wire disconnected.

 

The other wire is black as well.

 

Yeah, it seems likely that it may be old wires from an aftermarket setup. Everything still works with them disconnected, and there is no charge running through them at any point.