Topic: Ummmm....why did my wiring harness melt?

[zoo mob]

So, after my first overnight trip, bike dies going down the road, it was still running, just no throttle response at all. Pulled over, turned off the light, got her running again, a few miles later, dies again and won't start, go to autozone, get a battery, get the last 50 miles home w/the lights off. Ride it once in the dark, and it dies in a couple of miles. Charge it, hook it to a voltmeter and its reading 11.7 w/the lights off.

Next step, borrow a voltmeter and start checking things. Well, I took off my left sidecover and boom, melty wiring harness (I'll post pics tomorrow) The bike is a 73 750 K3, has dyna 3 ohm coils and electronic ignition (I haven't installed my hondaman resitor yet). I removed my rear turn signals to mount saddlebags right before the trip, clipped the wires and did not tape them up on one side. What in the heck is the culprit here? Too much juice from the coils, a turn signal wire grounding out? Thanks, and my God have mercy on my soul, I am so f-ing sick of this bike!

[Hush]

You would think that the fuses would have popped before a decent meltdown happened.
Wont be your turn signals as they are only on when you flick on for a few seconds.
I'd be looking for a rubbed wire on the frame, check under the tank, that cluster can rubb the plastic off real easy.

[zoo mob]

Don't know if its pertinent or not, but the night before the problem the bike was left with the lights on with the key out and the ignition in the third position, also, I do forget to turn the turn signals off sometimes, so that might still be the cause?

[Shenanigans]

Do you have the correct fuses in? Check them to make sure.

[TwoTired]

Didi it recently melt?  Or, did you buy it that way?

The charging system is NOT fused.  Reversing battery terminals will make that wiring melt in seconds.

Why did you clip wires instead of simply unplugging them?   It's usually male into Female and unplugging them leaves a powered connection insulated.

[zoo mob]

I'm in the process of trying to fix the problem, the assumption is that it was the wires at the rear turn signal. A couple of questions though: the only wire that seems to be fried is the green ground wire that runs the length of the harness, its fried at the ground to the frame, through a couple of the plastic connectors and as far into the harness as I've gone. The black wires that go to the signal are not fried. Is the ground likely fried end to end? I've not checked the fuses yet, and will as soon as I get back from work. The harness was not melted until just recently. Do these symptoms sound consistent with the turn signal grounding out? Also, can a wire be spliced into the plastic connectors, if its fried all the way into the connector, or should I splice all of the wires and put a new connector in (I've got one)? Here's a couple of pics. Thanks for the help, I want to get this thing back on the road while the weather's still nice!

[zoo mob]

Anyone?

[Sporkfly]

High resistance at the clips maybe? Turn signals should be grounded, it completes the circuit.

Any chance at non-blurry higher res photos? I'm having trouble picking out the melt... From the third photo down it looks like the charging system could be part of the issue, check for shorts there.

[Dunstall_74]

You mentioned you stopped and got a new battery.  Just wondering if it was possible your new battery has +- poles in the opposite possition as your old battery. I did this once and the smoke started to roll, like TwoTired said "in a matter of seconds."  It was mainly right around that plug your holding up too(the one by the rectifier).  That was my first instinct when I saw the smoke......Unplug that sob 
http://forums.sohc4.net/index.php?topic=33180.msg343448#msg343448

[zoo mob]

No, the batteries are the same. I'll try to get better photos tomorrow. I also installed a generic starter solenoid earlier in the season (just trying to think of anything vaguely related to the charging system.

[speedy gonzalais]

check all the earths make sure they have good connection also check the starter motor make sure it disengages after the engine starts, the melting is prob due to an overload on the circuit maybe to much power being drawn from something, Check the new solenoid, that uses the most power of all components, does the bike fire up strait away or turn over for a while? I know if i turn my 650 over for more than two mins things start to heat up,
As the earth cable is melted it points to a bad ground maybe.

[scooter2go]

Here's my two cents. I just got a 78 750k from my dad, stored 6-7yrs. trailered it home, started going through it and found the same thing, ground wire melted all the way to the rectifier. I replaced it and the plugs, now it's living again. Scooter

[bryanj]

Usual reason for the harness ground to fry is the main ground from battery to engine not making good contact at one or both ends

[zoo mob]

Well, I'm going to replace the ground wire as that is the only one that is melted, I've got a spare rectifier, soldenoid and regulator from a K0 750 lying around, will those work on a K3  750? Also, the bike does take f-ing forever to start sometimes, and it took a long time to start the morning that this happened, but I don't recall smelling any smoke, and I rode it for at least an hour and a half before it died.