[Keith True]

A good digital meter goes wonky on an A.Some say it is interference from the unshielded ignition,some say it is from the vibrating cutout,some say it is from the brushes passing over the bars on the generator,.Maybe it is a combination,or something completely different.Use LED bulbs for the tail,brake and turn,with an electronic flasher,and you should be fine.I found that if the voltage drops enough for the lights to drop off,they will recover and come back on.Then go off again,real fast.If they still do it with the engine revved up then you either have a ground problem,(likely) or the generator isn't putting out enough.(not really as likely)Thermal flashers really do draw quite a lot of juice.Put your hand on one in use,all that juice being used will heat that flasher pretty quick.