Sounds like the fuse is melting, not blowing from overcurrent. This is commonly caused by the fuse clips/fuse forming a layer of resistive corrosion at the interface between the two parts. This resistance generates heat which melts the fuse link. The fuse clip and the fuse should be polished so they are brite, shiny, and mirror smooth. The clips should also provide very good contact prssure on the fuse contacts. If the clips have gotten weak and lost their temper from the excess heat they will have to be replaced. Sometimes they can be bent back to give better contact pressure. I've seen chronic cases of this malady melt the solder connections on the back of the fuse block. (Probably due to a previous owner putting in larger fuses that have more mass to heat before they melt.) So, it might be a good idea to take the back off the fuse block and inspect there, too.
The heat buildup is interactive with the total load placed on the system. So, if you've added brighter/ more lighting equipment, the increased current flow through the resistive corrosion will generate higher heat byproduct, too. Cheers, Lloyd SOHC4#11 72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F, 78 750 Jules Jehu wrote: >Folks, > > I'm blowing the main 15amp fuse on my 550F regularly, but not because of >any detectable short in the harness or connectors, which all still look >brand-new and meter out just fine. In addition, the dead fuse is always >mega-hot, so I'm assuming that there is a problem with the generated >voltage regulation. > > Not knowing a thing about bike electrics other than possessing the ability >to do a bit of splicing, dicing and continuity testing, could anybody out >there give me an idea of what I should be looking for, and also methods of >diagnosis if there are potentially multiple causes ? > > Thanks, > Jules. > > > >
