Ignition and main fuse keep blowing 78 GS 1000 C

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  • Crawf
    • Jan 2026

    #1

    Ignition and main fuse keep blowing 78 GS 1000 C

    Hi Forum members,
    All of a sudden main and ignition fuses blowing.Cant find any obvious wire erosion, shorts or burnt out wires.Any theories appreciated.Electrics aren't my thing and local auto electricians don't like working on old bikes.No appreciation for the finer things in life.
    Regards Crawf.
  • tom203
    Forum Guru
    Past Site Supporter
    • Aug 2010
    • 8925
    • Norway,Maine

    #2
    Take out the ignition fuse- does the main fuse still blow?
    1981 gs650L

    "We are all born ignorant, but you have to work hard to stay stupid" Ben Franklin

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    • bobgroger
      Forum Sage
      Past Site Supporter
      • Jun 2013
      • 2481
      • Enumclaw, WA

      #3
      Long shot, but my 850 went through a bout of that. Turned out to be one of the terminals on the horn touching the frame.
      sigpic
      09 Kaw C14 Rocket powered Barcalounger
      1983 GS1100e
      82\83 1100e Frankenbike
      1980 GS1260
      Previous 65 Suzuki 80 Scrambler, 76 KZ900, 02 GSF1200S, 81 GS1100e, 80 GS850G

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      • Gorminrider
        Forum Sage
        Past Site Supporter
        • Aug 2012
        • 4803
        • British Columbia, Canada

        #4
        It's gotta be a clue that the lower-amperage ignition fuse blows along with the higher-amperage main fuse . I'd have a good long look at the wiring diagram for the bike and see where it's possible along the ignition circuits to do that....

        Have you done anything recently in the wiring or routing of wires? Too Often the last place fiddled with is the first place to look
        Last edited by Gorminrider; 07-27-2016, 10:24 AM.

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        • Crawf

          #5
          Found it !! I had put some new headlight brackets and lower bars on.In the process of putting it all back together some minor re routing had created a short under the key ignition.A wire was contacting the wire hydraulic casing from the clutch and shorting on the front end.It was lucky I was working outside and the light was fading.Noticed a tiny spark which probably saved a lot of forensics.
          Thanks for your tips.

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          • Gorminrider
            Forum Sage
            Past Site Supporter
            • Aug 2012
            • 4803
            • British Columbia, Canada

            #6
            Great! Thanks for reporting back! For sure looking for sparks should be added to the trouble shooting list! It's really hard to spot these if there's too much light ....

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            • Guest

              #7
              That's awesome that you found it, and it wasn't anything too major. It's also super awesome that you reported back with the answer, always nice to see a diagnostic thread that has a clear conclusion. Sent you an email with foam pictures as well.

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