Tim Shepherd wrote:It was the diode board. In the process of attempting to troubleshoot the ignition switch, I ended up with an alternator light that would not turn off, even with the ignition switch pulled and the brushes making no contact (?)! With the ignition switch in, the starter wouldn't turn. I had put in a new starter switch yesterday, before this trouble started, so I knew it wasn't that. Swapped starter relay and regulator, the ones on the bike were crusty originals, but still that light was on. Finally put in a new diode board, and then everything worked, except the oil light... fixed that in 5 minutes too. The ignition switch is still iffy, but I'm going for a ride!
This doesn't address your problem, but it does address the possibility of getting stuck on the road from an intermittent electrical problem in the ignition wiring.
A couple of my bikes have a toggle switch under the seat jumping the battery positive directly to the positive side of the two coils. I put it there at the time because I thought I was having electrical problems having to do with a corroded starter relay socket. (BMW chose to run the red positive 12V wire from the starter solenoid through the starter relay, thence to the ignition switch. This was particularly problematic with the under the tank master cylinders leaking brake fluid into the relay connector. Apparently that was a handy place to tie two wiring looms together.)
My fear was that if I hadn't done a good enough job cleaning the starter relay socket contacts and that the circuit would jiggle open, breaking the battery connection, and leaving me stranded away from home farther than I wanted to walk.
This is a lot of words to say that I thought keeping the toggle switched "hot wire" in place was a prudent thing to do. Plus having a switched "hot wire" in place seemed like a good way to ensure riding rather than walking home in case my starter relay contact cleaning job wasn't as good as I thought--or if I lost my key.
Of course, needless to say, with the toggle switch on you can't shut off your engine with the key until you turn the hot wire switch off.
And with the hot wire toggle switch on, and the ignition switch on, all of the important electrical functions will work just fine.
Just a thought.
Ken