Motorcycle Repair: Possible electrical overload, honda cb 550, amp fuse

Question
1978 Honda CB 550 K, 15,000 miles, just bought it.  Runs pretty well, been riding.  Yesterday, riding down the road, it just quit, like the switch was turned off.  "Main" fuse holder had gotten hot, to the point of trying to melt the plastic fuse block.  Don't know if the melting had occurred this time or some time in the past.  Wire at the fuse block had either been a bad connection or got so hot it un-soldered itself from the fuse block.  Re-soldered wire to fuse block.  When I put a new 15A fuse in, the fuse gets hot when the switch key is turned on.  It seems WAY too hot.  When I turn the brights on, it gets hotter.  Should it be hot or warm?  If it is an overload issue, where should I start looking?  It is NOT blowing the fuse, at least not quickly.  Thanks

Answer
Hey Terry...

Well... I'm not sure which fuse you are referring too. I haven't worked on a bike the age of yours for some time now, but I do know that Honda used more than just one fuse on that bike. If you are talking about the main fuse, then the problem is simple... the main fuse should be rated at 25 - 30 amps... but if you're talking about the headlight fuse, I would install a 20 amp fuse and see if it flows cooler. Fuses are designed to blow if amperage is present with no load to take it ( a direct short)... they will get really hot if the circuit deals with more amperage than the fuse is designed for... hence the heating factor. If a fuse blew in the past, and the owner installed a replacement that was rated less than what is required, you may see the problem you are now seeing. Try what I suggested and let me know if it worked... If not, we'll need to probe deeper...
Good Luck Terry.... Ride Safe!!

Jack