My electric start randomly up and stopped working one day after a short ride, but the kick start still did so I went home and got to diagnosing. Of course, I had to do this in the least efficient way possible, so I started with disassembling the start switch to see if I had a broken wire. Nope, but I did figure out how the throttle works! An hour and a half of testing continuity in pretty much the entire harness and we get down to ONE wire going into one of the relays under the side cover. Before I have a complete breakdown and tear apart the harness looking for a broken wire, I realize I have a spare relay and decide to swap it as a test. Turns out, that was it! Bike fired right up, been great ever since. *SIGH* So, if anyone else has this problem, consider this little widget. This was on an '87 for reference and wire color.
This is it's "mate". They are right next to each other under the right side cover, by the CDI. Note the white plug on the relay and opaque plug on the harness. The one I actually swapped out is black/black, PN ACA1212-1
This is the widget itself. For whatever reason, this one has a rubber boot on it, the white-plugged one doesn't: