OK I'm still chasing down electrical gremlins on the 72 500. I've found all uninsulated wires and replaced then. Now when I blip the throttle to about 5-7k RPMs the fuse blows. btw all grounds have been checked and cleaned. This one is a head scratcher becuase I can have the bike sitting and running for 15-20minutes going through the RPM range (synced carbs yesterday) but blipping the throtthle hard seems to be the only time this happens.