I had this problem on my 750 and also on a 550 that I sold. Other than obvious shorts or corroded connector, the regulator can be the culprit. My 750 would blow the fuse at startup when I would blip the throttle. Perhaps replacement wioth an aftermarket regulator or from a DOHC 750 would be the answer. Or a good rebuild/cleaning/adjustment. Just a few ideas
Don SOHC #79
