Electrical Nightmare - 1982 GS750T

[denouden]

I have a 1982 GS750TZ which I bought last summer planning to fix and ride this season. I cleaned the carbs last week as it's been sitting for over 4 years and gave it an oil change etc.

The problem I am having now is that the ignition fuse is constantly blowing as soon as you turn it to Run.

Upon furthur investigation, I noticed about half dozen wires that were fused together so I fixed all of them that I could see (And I did dig around as best I could). I did get it running after this (and it ran quite good actually) for a few minutes and then the fuse went again.

I have a couple questions. Is it possible that inside the factory "taping" of the electrical wires that there may be some bare/fused wires in there? Or is it farely uncommon that the protected wires would be the problem?

I noticed after the fuse went the last time that the wires coming from the ignition switch (or the Run switch - whatever that's called) were quite warm/hot. I also noticed that some of the wires behind the headlight were melted that weren't before I ran it.

Any electrical troubleshooting tips would be very appreciated. I do have a digital mulitmeter but am not an expert at using it. How would I check the continuity of the ignition wiring if the fuse keeps blowing and there isn't any current running through it?

Finally, anyone know the price of a wiring harness and if it would even be my best bet since there are now roughly 8 wires that are spliced and repaired and Lord knows how many that I can't see need repairing? How long does is take to switch it all out? (3-4 hours is a guess)

I repaired the wires by splicing them and using electrical connectors along with that insulator tubing that I "melted" over the splice so I'm pretty sure that my repairs aren't adding to the problem.

The ignition fuse is the only one blowing and all the other lights and whistles do work so I think the problem may be isolated to the ignition wiring circuit. This leads me to believe that replacing the whole harness may be a waste of money (and time).

Thanks in advance...

[Anonymous]

Find yourself a wiring diagram, they are fairly simple to read. Some one on this site it bound to have one they can scan and email to you, or you can buy a service manual which will have one along with lots of other helpful things you will need on down the road. Sounds like you have a major short in your wires. Pull out the headlight and look at the connections where the "melted" wires are and follow them where ever they go, along the way look for anything "unusual". My bike had a simular problem I ended up taking the factory "tape" off to better isolate the issue. To put it all back together I used rubber tape.

[SqDancerLynn1]

In your position it will probably require rebuilding the wiring harness
Get an assortment of cable ties & remove the tape wrap from the harness & use the cable ties to keep everthing together. Replace the burnt damaged wires. Then rewrap the harness, do not use electrical tape.
Try disconnecting the reg & stator to see if the fuse still blows

[denouden]

In your position it will probably require rebuilding the wiring harness
Get an assortment of cable ties & remove the tape wrap from the harness & use the cable ties to keep everthing together. Replace the burnt damaged wires. Then rewrap the harness, do not use electrical tape.
Try disconnecting the reg & stator to see if the fuse still blows

What would I use then, the rubber tape previously mentioned? I would imagine it would be easier to take the whole harness out?

Thanks for the replies...

[focus frenzy]

In your position it will probably require rebuilding the wiring harness
Get an assortment of cable ties & remove the tape wrap from the harness & use the cable ties to keep everthing together. Replace the burnt damaged wires. Then rewrap the harness, do not use electrical tape.
Try disconnecting the reg & stator to see if the fuse still blows

What would I use then, the rubber tape previously mentioned? I would imagine it would be easier to take the whole harness out?

Thanks for the replies...

you use electrical tape to re-wrap the harness, that is what is originaly used, and is what is used to this day.
the manufacturer just uses a much much bigger roll, I have been to a place that manufactures harnesess for street rods and they have machines that spin 2 foot diameter rolls of electrical tape around the wiring bundles as a person slowly passes it through the machine.

[denouden]

Thanks for the hints...I have a guy checking to see if he has a wiring harness for me for fairly cheap. Depending on the price and/or availability, I have a friend that is more adept at electrical who is going to help me go through it all and see if we can rebuild it. Since a GS member has offered to send me a copy of the wiring diagram, I should get my baby going one way or another.

I've heard that disconnected the regulator may stop the fuse from going....any more info on this? Could a problem with that or the stator cause an electrical short circuit?

Thanks again...

[SqDancerLynn1]

A problem with the stator/reg can cause the fuse to blow intermittanly & also blow when the ign switch is turned on or off Your bike will run fine with them disconnected for testing. Their are other wiring issues that will also cause the fuse to blow. We have to start somewhere so why not check the easy things first

[nabrams]

When an R/R deteriorates drastically it will blow the main fuse almost as soon as you start the bike. But it sounds like you're seeing the fuse blow before you even get the chance to press the starter button - if that's true, then you're looking at a short circuit. If you can get an undamaged wiring harness, that's a great way to solve the short circuit, but you risk ruining your new wiring harness if you don't check your stator, R/R and fuse block.
If your R/R is causing an over-voltage to the system and the fuse doesn't blow soon enough, then you can end up frying bulbs and/or wiring - this is what happened to me. Luckily my fuse blew only seconds after starting the bike, so the damage was minimal (only a few blown instrument bulbs and some semi-melted wire insulation).

[denouden]

When an R/R deteriorates drastically it will blow the main fuse almost as soon as you start the bike. But it sounds like you're seeing the fuse blow before you even get the chance to press the starter button - if that's true, then you're looking at a short circuit. If you can get an undamaged wiring harness, that's a great way to solve the short circuit, but you risk ruining your new wiring harness if you don't check your stator, R/R and fuse block.
If your R/R is causing an over-voltage to the system and the fuse doesn't blow soon enough, then you can end up frying bulbs and/or wiring - this is what happened to me. Luckily my fuse blew only seconds after starting the bike, so the damage was minimal (only a few blown instrument bulbs and some semi-melted wire insulation).

Thanks for the heads up...either way I do it (repair or new), I'll be sure to test everything out before doing any more damage...

How can I test the R/R without damaging the rest. The things I've read on here seem to say to test it whilst the bike runs. Is there a way to test it without running the bike, thus preventing it destroying other componants? The bike will run if I take the plug out of the recifier yes? (Which would prevent it from damage?)

Thanks again everyone.

[Anonymous]

Denouden,, If your intrested in a wiring diagram I have one scanned out of my clymer manual that I could e-mail you if you like.

[nabrams]

The "stator-papers" in the "garage" section of this site have a test for the R/R when it's disconnected from the bike (read the whole document - you'll find the test). It involves measuring resistance. The "connected" test involves measuring voltage. The document tells you to do the "connected" test first, but there's no reason you couldn't do the dis-connected test first.
Besides, in your case, you can't get the bike to run, so you might as well do the dis-connected test first while you're waiting for the new wiring harness.
Please be aware that you must have an accurate multimeter (about $40) and the results of the test should be exactly as stated in the document (or very nearly so).
My bad R/R failed the disconnected test miserably.

[SqDancerLynn1]

A $10 digital meter will work fine

[denouden]

A friend and I went through the harness last night and although there are about 8 wires that are spliced and redone , the harness seems to be ok. We fixed a couple of the connections that looked a little questionable and we hooked it all back up to the bike and it didn't blow the fuse. So, we installed the coils back on the bike and - blown fuse. Although hard to see, it looks as is the aftermarket Dyna coils were grounding out to the frame. The "hot" wire connects to the coil right near the mount on the bike.

So, we put an extra spacer in there, and problem solved(?). Tonight I plan to reroute the harness back through the bike and hopefully the problem will remain solved.

Thanks to everyone for your suggestions and help. The wiring diagram from mikemilburn really helped.

[denouden]

Still problems

I have eliminated the short...no more blown fuses. Now I don't seem to have a good spark; she won't fire up. If I lay the plugs on the block, nothing, if I hold the spark plug a 1/4 inch away from the head...good spark. WTF? Any idears? I got the coils tested, they are fine.

Is has aftermarket Dyna coils, is it possible the power leads are reversed? There are no markings on the coils.

Thanks.

[SqDancerLynn1]

There is no polarity on the coils. Have you checked the plug caps?