30A blown and other assorted problems

Hi, All. I'm having problems blowing the main fuse on my '82 Spectre 750. All the wires (as far as I can tell) look good. I wired a 12v light in series and checked for shorts. I didn't turn up anything after checking through everything I could find. I took the fuse box out of the bike and slid off the plastic cover behind the fuse clips. The plastic is melted away where the red/white and solid white wires are hooked into the main fuse clip. The white wire is pretty burned up right where it's crimped into the clip. I'm hoping switching to the modern style fuse box will eliminate these problems.

Also, after a quick test ride I parked in the garage. I shut the bike off with the key but the electrical stayed on. The bike died because I don't have the idle set right so it probably would have kept running. I took the main fuse out and it shut down. After the bike cooled off I put the fuse back in and everything was functioning normally. It hasn't done this again for a few days.

Today I polished the fuse clips with a bit of sandpaper. Everything was fine before the polish. Now after the treatment when I went to put the 30A fuse back in, the fuse sparks and the lights come on with the key in the "off" position. It has the original ignition switch in it. I wouldn't be surprised if it was bad. I'm wondering if the two problems are related.

Any advice on either problem would be helpful. Thanks in advance!

The ignition switch has a connector, inside the headlight bucket, so you can test it there. The wires for your main fuse sound like they are cooked. So if you replace the fuse panel, also replace at least the bad section of wiring, it is building up resistance and that is shown as heat, melting.

I'll be rewiring all the burned wires running into the fuse box. Now I just need to find one that will fit.

How do I test the ignition switch? Should I check the resistance from the connection behind the headlight? The problem is definitely intermittent. I just went down and popped the fuse back in. This time the fuse went in and the electrical stayed off. When I turned the key to "on", everything comes on like normal, and turning it to "off" shuts it off.

I think polishing the fuse clips with sandpaper helped a bit. Before, I had to slide the fuse back and forth to make contact before the lights would come on. Now I can slide the fuse back and forth and it stays lit.

With my experience, cleaning the fuse clip defiantly helps to prevent main fuse from blowing out short while, but eventually, the fuse will start blowing out again. 
I cut main fuse wire from fuse box and implanted blade type fuse holder that I got from eBay by less than $10. My understanding is that the main fuse melt by heat that is created by the poor contact at the fuse clip. Before I added blade type fuse, the fuse box got very hot (too hot to touch) few second after turning ignition switch to on position, but after this modification, I don't feel any heat from fuse box any longer.
 

It is only my assumption but when the main fuse blow, the melted meta went out from glass tube and got inside of the fuse box and connect / bypass hot wire to head light fuse connector, maybe???

I'm ordering the new fusebox today. That will eliminate at least one more 30 year old component. By the time I'm done, I'll have replaced or rebuilt nearly everything! At least the motor is solid. : )

Getting her going one step at a time.

UPDATE: After putting the blade style fusebox in, I've had zero issues. I've put 5,000 miles on it since then. In my opinion, this mod is a must. Cost me $30 and less than an hour of my time.