Fried Wiring When Trying To Start Bike, Need Damage Assessment

What I mean by an isolated engine is cases where the engine is poorly grounded to the frame. This is usually encountered after a newly painted frame. The engine simply doesn't touch the frame because of the heavy paint. The starter motor being attached to the engine cases means it has to find a different route for the cranking amps required. They will run through the ground wire in the harness (black) and burn the wire. I've also seen paint so heavy in the bolt hole for the ground cable, just behind battery box on the frame, that it would ground good enough to run lights and kick start but smoke the harness if you hit the starter. And last is the battery box ground. Never run your ground cable to the battery box. It has rubber dampers on all 4 mounts and will send all starter amps through those tiny wires in the harness and they just won't take the load. I still think you have a ground issue but can't imagine how with what you say you have done service wise. Hope this helps.

Looks like my ground cable is connected right to the damn battery box. Yes, even with my infantile understanding of motorcycle electrical issues, I can see the rubber dampers that you mentioned and why not to try to ground there. Damn PO!

I wish I had recognized this much earlier on my own.
 

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like to one of the starter bolts (longer bolt if need be)

I haven't re-installed my starter motor yet, but you're talking of grounding to frame on this starter motor mounting bolt and running to NEG on battery, correct?

Ya gotta dumb it down for me, Bro!
 

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You found your problem so you really don't have to go to that much trouble. Just run your ground cable from the battery to the frame. There's a threaded bolt hole right behind the battery box on the frame. It should be on the throttle side. Make sure the paint is scraped away . That will be all the ground you need. Hope this helps.
 
Information:

Pamco
Ultimate High Output Coil
NGK Iridium Spark Plugs (#4055, Bpr7Eix)
Yuasa YTX14AHL-BS Battery

I recently rebuilt/re-jetted my BS38 carbs, adjusted cam chain tensioner, adjusted valve clearances, set timing and synchronized the carbs. All was well....

When using the electric start, the bike would either start immediately OR it would go Rrrr rrrr rrrrr and then nothing (while I was holding down the Start Button). When it would it do the latter, I first noticed smoke, then red-hot wiring and then toasted wires & insulation.

Fried wiring. Damnit!!

See pics.

1) What are some possible causes of this wiring melt-down?

I notice that Mikesxs description of this Coil indicates not to leave the ignition on w/o the bike running. When I tried to start the bike & nothing happened, then the wires heated up, I only had the ignition on for a matter of seconds - did NOT leave it on for any extended periods.

I have to wonder about faulty wiring, damaged insulation, etc... I notice that alot of my wiring connectors are brown (as opposed to clear) looking looking like they've gotten too hot.

2) In light of the damage, am I looking at replacement of the main wiring harness? Any chance of successful repair at affected areas? I see that Mikesxs carries a harness for my XS650C for $90. Comments on Mikesxs wiring harnesses?

I have to wonder whether this could/will occur again (even with new wiring) if the root cause is not determined....

I am not electrically-inclined and have no appetite for installing a new harness (unless a littlebill31-quality step-by-step video tutorial is available.. I'll more than likely have a Shop do this wiring job for me. Cha-ching.

3) Is there a way to Check the functionality of my Pamco and Coil to see if they're OK?

4) If I had started the Bike via the Kick-Starter (and NOT electric start), might this NOT have happened, since using the Start Button seemed to be the thing that started the Wiring BBQ?

Lots of questions, I know....

After all of the mechanical and limited ignition system work (i.e., Pamco & related) I've done over the past several months, I am pretty discouraged right now... :(
From what I see looks like a PO has been there. Looks like a short. Can't hurt the harness anymore. Take a box opener and slit the covering & remove it. Look and see which wires are krispy. Time to solder. Replace the burnt areas one wire at a time, with the same gauge wire. Color coding don't matter much here because it will be taped up, and the ends will be the right color. When you get all of them tape up the splices, then wrap the the harness with tape to replace the covering you just cut off. Now if you want pretty, Just buy a harness, and pay someone to do it. Even if you have to buy a soldering outfit it's way cheaper than that.
 
When you do solder in new wire and such, use heat shrink tubing over the joint. Less bulk and better protection. You can even get it large enough to cover the whole harness.
Leo
 
You found your problem so you really don't have to go to that much trouble. Just run your ground cable from the battery to the frame. There's a threaded bolt hole right behind the battery box on the frame. It should be on the throttle side. Make sure the paint is scraped away . That will be all the ground you need. Hope this helps.

Lanny, I've not finished my wiring harness (ordered one from Mikesxs) work in the headlight area (XSLeo helping me throught that mess), but as far as re-locating the battery ground, you can see where I had in mind in 1st image (just to left of fuel tank bolt location). I did find where you were referring to and will probably relocate my cable to rear of battery box since I like the fact that its a threaded hole and I don't have to secure with a nut and lock washer like I do now, which may be prone to becoming loose. - Thanks! - John
 

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I think I'd located to the threaded hole behind the battery box. Thats what it's there for and you're right about the other being prone to loosening. Tip on routing your harness. Layer new one on as you take the old one off. Makes layout much easier. Glad you're getting it straightened out.
Don't think I mentioned it but i'm helping a friend restore a 76 just like yours.
 
I think I'd located to the threaded hole behind the battery box. Thats what it's there for and you're right about the other being prone to loosening. Tip on routing your harness. Layer new one on as you take the old one off. Makes layout much easier. Glad you're getting it straightened out.
Don't think I mentioned it but i'm helping a friend restore a 76 just like yours.

I've plugged up my new harness all of the way up to the headlight area. I've hooked about all of the colored power wires up front. Not too sure about some of them...

Thanks to XSLeo, I learned that wires that I thought were black ground wires are actually dark green and chocolate, such as those coming out of the front turns.

Since you're working on a buddies 76 (hopefully with full OEM or non-modified wiring like mine), I hope you can help me out as I finish making connections in the headlight bowl. Might be better if I shoot you a PM now and then when I have specific questions.

Are you helping your friend with his C in person or over the Internet?
 
Here's an update on my wiring progress. Everything is working as it should except for the following:

1) Stop Lamp does NOT light up when I depress Rear Brake Pedal.
Stop Lamp DOES light up when I squeeze Front Brake Lever.

2) Stop Light does NOT light up when I depress the Rear Brake Pedal.

3) Stop Lamp DOES light up when I turn on the Headlight (Hi & Lo Beam).


I assume #3 should NOT be happening.

I'm guessing that I have problems with yellow wires and/or blue wires.

I checked the Taillight/Stop Light Bulb and the filaments appear to be fine.

The Yellow Wire on my headlight plug is labeled "Drive" for what its worth.

Can anyone quickly diagnose my miswiring?

I've come a long way from a fried wiring harness coupled with electrical incompetence!
 
First check the bulbs. Take a hot jumper wire from the battery + and touch it to the contacts on the end of the bulb one at a time while grounding the case to a good ground (frame, motor, or battery negative). If both sides work the bulb is good, if not get a new one. Look inside the tail light socket. It could be corroded. If so clean with contact cleaner. Check the contacts in the light socket with a Volt Ohm Meter. One contact at a time. With just the key on, one should battery voltage That is the tail light. The other is brake. See if you have voltage there when you use the brakes. If you don't check the brake light switches with the meter on the lowest setting on the Ohm scale of your meter Working the switch should swing the needle on an analog meter, or change the reading on a digital one. No change, your problem is there. It's not unusual for these to get cruddy. Especially if the bike has sat a long time. Some can be salvaged with contact cleaner squirted at the plunger while working it. If this don't work get new switches. If you find no problems, check your wiring again.
 
If your tail/brake light is stock, it has a blue and yellow wire. The blue wire is the tail light, the yellow is the brake light.
If your brake light lights when you turn on the lights, then you may have the yellow and blue wires crossedat the tail light.
One little tip, when using your meter, voltage is with power on, ohms is with power off.
On the headlight the yellow is the high beam or drive. You have to be sure not to hook the high beam yellow to the brake switches yellow. Not a hard mistake to make. I think they should have chosen different colors for those. Using yellow wires to hook to the safety relay, the headlight and brake lights can be confusing. Each one should be different colors.
Leo
 
I've seen this happen before on other bikes. You either have a bad ground on the battery negative cable to the frame or an isolated engine. Lots of frame paint will prevent the engine from grounding to frame. When you push the starter button in the starter motor is trying to draw all it's amps through the tiny wires in the harness. If you install a new harness it will burn up too if the problem isn't found and corrected first. Good luck.

Exactly my thoughts when reading through this thread. However the corroded switch is definitely likely to be a contributory factor too.

Poor connections cause resistance to the flow of electricity which in turn generate lots of heat. Make sure all your connections are super clean particularly battery and switch connections...
ooops i see Rebel has already covered this.
 
All electrical connections are now complete and everything is working great. Root cause (as Identified by Rebel) for wiring melt-down was poor grounding of negative battery cable to rubber dampered battery box. I now have a good ground in a threaded 6mm hole toward the rear on frame). I can and will blame that on the PO.

Problems that I had and eventually solved (with everyone's help) included corroded connections, undetected un-plugged wires, poor grounding and in the headlight area some misidentification of wire colors (including those darn chocolates).

Thanks again for all of the help!
 
thats great news... glad its sorted well done. This thread is sure to help other owners some point in the future so its good that it has a solution:thumbsup:
 
Thanks, peanut!!

I'm never short on blunders, ill fortune and misadventures that I'm willing to share and document with lots of images for the public good. :D

Quite honestly, having numerous problems on my C has given me a lot of hands-on learning opportunties and invaluable experience.

Edit:

Just re-read everything in the thread. Aside from getting the wiring done (see other thread that I elongated quite a bit named "Headlight Wiring Question" which was an adventure it itself), I'm happy about a couple of things that I worried about from the get-go, Namely:

1) Was CERTAIN that I'd have to haul bike to a Shop & pay someone else lots of $$ to do the work for me. I might have more hair on my head, but my wallet would have been thinner and I wouldn't have learned a damn thing about my bike. I was inspired along the way in this thread to do the work myself....

2) Was nearly CERTAIN and worried that I'd fried my Pamco and new Ultimate High Output Coil. They were not affected.

I put a LOT of time into testing the solenoid and the Starter which led to dealing with the reduction gear box, seals, etc. That was a pain in the ass, but I can handle anything needed in all those areas.... I can now dismantle my Starter, test the armature, clean the commutator, solder on new brushes, etc.

Now, I'm moving on to new misadventures....synchronizing my carbs (which is what I was working on when my wiring went up in flames)...
 
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there ya go !:thumbsup: you are now starting out on one of life's great adventures which few are lucky enough (or smart enough) to experience.
Very satisfying & very rewarding to spanner your own vehicles some might say theraputic :D

Well done anyway
 
I know this is an old post but it may help someone out.

Had similar issue with a Yamaha Kodiak Quad.

Took a while to figure it out.

The starter relay would repeatedly click and the wiring would smoke sometimes when hitting the start button. Sometimes the bike would start immediately without fault. The condition worsened.

It turned out to be a dirty connections on the large wires that transfer the bulk current to the starter motor (and not sure if I remember rightly, the earth straps as well that ensure everything on the frame and engine was electrically "grounded" I think I cleaned all of the terminals of these too).

The current was being fed alternately via the small wires and conductors not designed to carry such load and therefore was overheating producing smoke.

I am sure if I held the start button down with disregard for the smoke, or wasn't lucky enough for problem to be so immediately visible. Damage would have resulted.

Hope that helps someone out in the future.
 
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