Too simple, but thoroughly clean and then tighten ground wire at both ends, but ignition switch very likely, especially that early model. If loose, and about to go, you may get the controls to light up for a second while either turning the wheel (
@TURBO200R4) or moving the harness where it enters the key switch, while it's turned on, of course. If not, you may have a broken wire inside the switch. I have the Roadster that
@Gregger linked you to with the repair. Mine was intermittent at first, so I knew that was the problem before tearing into it. I think I know how, but someone more qualified can tell you how to check the wires to the switch for power (which ones, etc.)
If I had to bet money, the switch is your issue. Be sure to rewire it yourself or buy the kit to reroute the power to the lights away from the switch. I did it myself, cause I'm cheap, but I would just buy the darn kit next time from eastern beaver.
What if you want the low beam switch ?
www.r3owners.net
Eastern Beaver H4 headlight kits for motorcycles
easternbeaver.com