Actually, my 78SE is wired (from the factory) so that I can have the headlight on with the engine off, if I wish. My bike has a "Headlight" switch that bypasses the safety relay. I leave the "Headlight" switch off normally, so my headlight stays off during starting, and once started the safety relay turns the headlight on automatically.
The "Headlight" switch was deleted by Yamaha on 79 to 83 models
I wonder how much money they saved by doing that???