Main fuse blowing out... help!

I'm preparing to get my bike back on the road soon and wanted to aleviate this problem before I drive it 200 miles from my home in Pennsylvania to the Naval submarine base I'm currently stationed at in Groton, CT. I've had the main fuse blow out several times (at least 3) last summer usually at a high RPM under heavy acceleration. The bike is a 79 1000 LTD with Dyna S coils and ignition. When this happens the plastic very near the fuse is slightly melted. For what it's worth, the only other electrical problem I'm aware of is the fact that my hazard switch makes the blinkers flash very dim and erratically. I wasn't sure if I should just step up the amperage of the fuse or if that would be a poor choice. Any help is greatly appreciated.

Don't put a larger fuse in there, that's trouble waiting to happen. It could be some dirty corroded connections in the fuse block, take a look there. You can open up your hazard switch and check there too. Look in your wiring diagram and find the bullet connections in the harness for the hazards, they may need cleaning.

You also may have an issue in the charging system, putting out too much voltage. Check the filebase for the Electrosport troubleshooting chart and go thru it.

But I'm betting it's dirty connections creating too much resistance, thus heat and melting plastic, popping fuses.

Mkosharkii wrote:

CT. ...I've had the main fuse blow out several times (at least 3) last summer usually at a high RPM under heavy acceleration. ... When this happens the plastic very near the fuse is slightly melted. For what it's worth, the only other electrical problem I'm aware of is the fact that my hazard switch makes the blinkers flash very dim and erratically. ...I wasn't sure if I should just step up the amperage of the fuse or if that would be a poor choice. Any help is greatly appreciated.

Short somewhere in the lighting circuit, probably associated with the turn signals. Could be anywhere in the circuit.

Had a similar occurance on my '78 C1A, turned out to be a short in the left-bar switch block. When de-copping cop bikes, the orangutans in the muni service garages were likely as not to use a hacksaw as their tool of choice on KZ C/P harnesses.



Heavy acceleration: regulated voltage, massive current increase; weak link gets the hottest firstest - the fuse - and anything close by, like insulation.

Jamming a ceramic fuse from Granny's basement box ain't gonna do much for the rest of your harness - bit it *might* make a neat-o looking miniature thunderstorm behind your sidecovers - make sure to ride at night.... :evil: And you might wanna carry one of those small fire extinguishers...

Get a wiring diagram and start tracking, starting with the turn signal lines.

Another possibility is that ball of spagehtti inside the headlight bucket; all kinds of electrical Crips & Bloods hang out in there.

Best of luck...

del

Hi. I had a similar problem a few years ago and it turned out to be one of the connectors on the voltage regulator. It was pretty easy to spot as the connector felt loose and was a little burned. Once fixed, the problem never returned. Ed

I had a short once, and even after I fixed it enough of the plastic fuse holder had melted so much that it could no longer make a good connection to the fuse itself. After I replaced it with blade fuses, it all worked fine.

650ed wrote:

Hi. I had a similar problem a few years ago and it turned out to be one of the connectors on the voltage regulator. It was pretty easy to spot as the connector felt loose and was a little burned. Once fixed, the problem never returned. Ed

Same problem I had, dirty RR connector was almost MELTED!. It was popping bulbs left and right. That electrosport diagram was a lifesaver!

Yea, the melted plastic is the key to this.
Fuse blown black, plastic surrounding it "not" melted=shorted wiring.
Fuse melted at the end/ plastic surrounding clips melted=corroded fuse clips causing the fuse to heat up and burn out.
Your problem is the clips.
This is an extremely common thing on these bikes. Every time I ride on a pitch black night ride, I think about those clips and hope they don't heat up and burn the fuse out cause you're in the dark when it happens.

Cut the old fusebox out. Solder in and shrinkwrap you some nice shiny new )orange) waterproof spade fuse holders. $1.99 each from Autozone or your supplier of choice.

Pull as many of your connectors apart as you can find and give them a good spray with "contact cleaner" ($5.99 from Home Depot).

Solder and shrinkwrap any connections you can.