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  1. #1

    Default 76 Ironhead XLCH short circuit issue

    Hey guys, this is my first post but I have been using the forums here for about a year now working on my 76 ironhead. Basically I've torn the thing down, and rebuilt much of it, getting it dialed in ready for that first ride. But I hit a snag today that has me stumped. So I am doing a rough chop on the thing, swing arm style but lowered the back suspension so needed to chop the rear fender and get it a bit higher off the wheel than it was. I didn't realize though was that part of the metal fender was touching one of the little boxes thats tucked between the wheel and the battery (not sure what its called). Anyways I went to start it and the fender caused a short, and then white wire going from the starter to said little box went up in flames and almost blew me right up. But pulled the wire, re rigged a new one and went to start it again, but now get no spark. I've tested the ig. coil and its only giving me about .1-.8 ohms on resistance so I figured either its frigged or my multimeter is no good. I ordered a new coil but am not sure if I fried anything else in the process. I checked and the positive side of the coil is still getting nearly 13 volts when the key is on, but the negative side going to the points is getting nothing when the wire running to the points is connected. When I take the wire off, the negative side of the coil reads the same 12.9 volts or whatever (but the points still read absolutely nothing). When it cranks, I usually see a little spark between the points when they open, but that also has absolutely nothing. Could I have fried the condenser? The Generator? I know my description is a bit vague but I am keen to learn and literally any advice out there is much help. Thanks a bunch.

  2. #2
    Senior Member

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    Join Date
    Aug 2009


    I'm guessing you shorted a breaker
    Get yourself a factory manual
    Stock wiring diagram will show white wire is for your ignition circuit.
    Yep, you probably fried the coil. Should be 5ohms for points.

  3. #3

    Join Date
    Dec 2018


    Sounds like your fender shorted the batt terminal of a breaker, and the white wire that leaked smoke was running power from the pos batt cable on the solenoid to the breaker, and that would make it the main breaker. Do I have that right? If so, the fender should have shorted that wire any time it touched the breaker post, switch on, switch off, wouldn't matter. Does that sound correct?

    If so, that little episode should not have had any effect on the ignition system, or the generator for that matter.

    With the ignition switch on, the pos terminal on the coil should read near batt voltage (minus drops through the switches and wires). With the point lead hooked up, and the points closed (as they usually are), the neg terminal on the coil should read zero, because the points are GROUNDING it, as they should be.

    If the primary resistance of your coil is really 1.8 ohms, it's toast, but that might not have anything to do with the ugly episode.

    You really are going to have to familiarize yourself with your bike's electrical system in order to even ask good questions, much less diagnose the problems. The HD service manual for your model is a must read, and has a full wiring diagram for your model in the back. Take the advice of an old mechanic, and for the love of God use the factory wire colors when you work on the harness, so you or someone in the future can figure it out.


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