Shuts off when I squeeze front brakes

[Danny Crawdad]

Okay, so this is a new one -- one of those problems that didn't exist before I parked it last time . I went for a quick ride today, and was running fine for about the first half hour of the ride. On the way back home, the bike stalled at a redlight. I figured it was a fluke, and went on my merry way. Next red light, it does the same as soon as I come to a stop with my hand on the front brake.

I restarted it and pulled into a parking lot to check it -- when sitting at idle with the clutch pulled in, squeezing the front brake lever and illuminating the brake light causes the bike to act as if the ignition has been cut off.

At first it would come back on immediately when I cranked it, but that started getting iffy. At some points, the bike would die, with the oil light and everything else off, and won't crank. After a few seconds, I would hear a "click", and the neutral light and oil light would come back on, and I could crank it easily. I rode home using the rear brake (which doesn't have the brake light switch hooked to it right now, waiting on a new one in the mail) to stop at lights. When riding, there's no issue.

Now that I'm home it doesn't seem to be doing it. The lights on the gauges (neutral light) will dim when I squeeze the brake. Battery resting voltage is 12.6v, at idle is 12.9, and rises to appropriate levels when I increase RPM.

I did recently have the brake light switch disconnected from the brake lever last week when I rebuilt the front master cylinder.

Any ideas? . It seems to me that it can only be electrical.

[DGXSER]

IT definitely sounds electrical. My best guess is you got a short in the wires for the front brake light that is grounding out or to the wires of the ignition system. May be something up in the front headlight bucket where all wires come to meet on an XS1100.

[Danny Crawdad]

Great idea on the bucket -- the brake light switch has been replaced at some time, so it had been spliced in (but pretty well). Problem was, their electrical tape sucked and was unraveling. Only thing I can think of was it might have grounded against the bucket when I closed the circuit by hitting the lever.

I put some shrink tubing around it and hit it with my heat gun, then re-arranged everything in the bucket and inspected all the connectors, and didn't see any evidence of other problems. Connectors were clean, insulation intact, etc.

Went on a sunset run and it did fine. I figured worse case I'd pull the brake light switch and ride without brake lights back home if I had to . But I didn't have any more issues, hopefully that'll continue to be the case!

[bikerphil]

If you still have the glass type fuse box, I would replace it with a blade type unit. If you lose all power including the dummy lights it could also be a problem with the ign. switch plug in the headlight bucket. The contacts in the ignition switch itself could also be bad.