Was riding today and when I got back my headlight was out. I pulled the bulb and it looked fine. I plugged it back in and hit the starter and it acted like the battery was dead, charged it and still didn't work. Got a new bulb from auto parts store and plugged it in, both high and low beam worked. Put it back together and started it up and the light was out again. Neither high or low beam worked, not even the high beam light on dash. Fuse is not broken and has power but not the headlight plug itself. Don't know what's causing it.
Sounds like your starter button is sticking just enough to cut the headlight but not engage the starter. Try physically pulling the start button out and see if that helps. Pretty common on those older VF style switch assemblies.