My 1991 F2's headlight stopped working a few weeks after a I low-sided (on right side). The crash was slow (gravel in corner) and gentle, I only had to replace footpeg bracket. I am not sure if this impact caused the issue or if timing was coincidental.

After ruling out a blown bulb, I spent an hour or 2 with the multi-meter trying to find the cause of the non-working headlight. It turned out to be a rather tricky thing to diagnose as all the wires and connections looked good and the switches were good/crisp.

Searching this forum resulted in a guess: starter button has built-in headlight interrupt, so it is not "reconnecting" after starting bike (starter button works to turn bike on). I went back and disassembled the right-hand switch cluster, despite everything looking perfect. I then (luckily) noticed a VERY tiny piece of white plastic was missing from the "retaining" clip-thing that holds the wire-connection-disc-thing in place... I could push down on the wire-connection-disc-thing with my finger (when starter button NOT being pressed) and the headlight would turn on! I know this is confusing to write/read about, and the "suggestion" I found on this forum was just very basic and without pictures/details. I have tried to explain with pictures below.


Switch housing, showing white-plastic-retaining-clip-thing, with wires and black-plastic-disc-thing removed. (above)