blown main fuse

[Matt Isaacs]

Hey all,

First time post here after buying a 1980 SG model. The bike is in beautiful shape, completely stock and unmolested, with only 6k miles on it. When I first got it, I replaced the chopper bars with a black dirt tracker bar. Couldn't get a spark until I checked this forum and learned I had to sand down both ends to get a ground under the turn signal switch and the starter. Once I sanded it, the bike fired right up and ran fine.

I spent the weekend improving some of the basics: rebuilt fork, replaced rear suspension and brake pads. But when I tried to start it, it blew a fuse. Then I noticed the left turn signal switch was loose (from when I put on a bar-end mirror). When I tightened the turn signal switch and replaced the the main fuse, the bike fired right up. But while I was letting it warm, it died after about five minutes. And again there was the blown main fuse. Now every time I replace the fuse and turn on the power, the fuse immediately blows. I checked inside the headlight switch, but there don't appear to be any loose or burnt wires. Sanded and cleaned the handlebar again. But nothing.

Any ideas?

 

[mrtwowheel]

Welcome to the forum. The headlight bucket is notorious for chaffing/cutting the insulation off of the wires and causing a short. Check the wires where they enter the headlight bucket.

Scott

 

[fredintoon]

Hi Matt and welcome,
like Scott sez, most likely something happened to the wiring in or around the headlight bucket or perhaps
one of the bar switches when you were working on the bike.
And if you mistake the black and the dark brown wires for each other, that'll do it, too.
It cost Mr. Stupid a whole bunch of fuses to find that one out.