sparks/arcing from from to front of Gas tank

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  • ryonker
    • Jan 2026

    #1

    sparks/arcing from from to front of Gas tank

    I am getting this really small spark/arc that seems to be jumping from the frame to underneath the front of the gas tank. I only notice it in my garage when I turned the lights down. Bad spark plug wires? Bad ground somewhere?

    I have a 79 750.

    Thanks for any ideas.

    Rick
    Last edited by Guest; 04-20-2015, 01:29 PM.
  • JTGS850GL
    Forum Guru
    Past Site Supporter
    • Aug 2013
    • 9735
    • GA

    #2
    It's definitely ignition coil related. Could be bad wires or the coil is not grounded out properly. Check for any cracked wires or plug caps. Check the screws that secure the coils to the frames as well. Might consider this an opportunity to upgrade your plug wires and caps.
    http://img633.imageshack.us/img633/811/douMvs.jpg
    1980 GS1000GT (Daily rider with a 1983 1100G engine)
    1998 Honda ST1100 (Daily long distance rider)
    1982 GS850GLZ (Daily rider when the weather is crap)

    Darn, with so many daily riders it's hard to decide which one to jump on next.;)

    JTGS850GL aka Julius

    GS Resource Greetings

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    • Steve
      GS Whisperer
      • Jun 2005
      • 35924
      • southwest oHIo

      #3
      I will second the notion that your plug wires need to be replaced. Evidently at least one of them is leaking to the tank, which could make things a bit "interesting" if you happen to touch the tank and a ground at the same time. It could also be "interesting" if there happen to be some fuel vapors hanging around the vicinity.

      I would look into replacing those wires QUICKLY.

      .
      sigpic
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      • 1980GS1000E
        Forum Sage
        Past Site Supporter
        • Aug 2007
        • 1664
        • San Diego, California, USA

        #4
        Very interesting. KaBoom.
        Current Rides: 1980 Suzuki GS1000ET, 2006 H-D Fatboy, 2021 BMW K1600B

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        • Brendan W
          Forum Sage
          Past Site Supporter
          • Jul 2013
          • 4920
          • Wexford, Ireland

          #5
          Just thinking, is the spark going the other way? Frame to tank seems odd as the tank is more or less isolated. However it's much easier to think of a duff ht lead charging up the tank which then has to dump it to ground.
          But then charge goes opposite to current........................... My head hurts.
          Last edited by Brendan W; 04-21-2015, 04:48 AM.
          97 R1100R
          Previous
          80 GS850G, 79 Z400B, 85 R100RT, 80 Z650D, 76 CB200

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          • ryonker

            #6
            Yes, I think you are correct. Somehow (bad plug wire likely) the tank is getting charged and then grounding to the frame. Hope new plug wires solves it since that's easy (-:! BTW, it's a 1979 750, but I put an electronic ignition in and swapped out the OEM coils for the green Dynas.

            Thanks everyone for your responses!

            Rick

            Comment

            • posplayr
              Forum LongTimer
              GSResource Superstar
              Past Site Supporter
              • Dec 2007
              • 23673
              • Tucson Az

              #7
              Originally posted by ryonker
              Yes, I think you are correct. Somehow (bad plug wire likely) the tank is getting charged and then grounding to the frame. Hope new plug wires solves it since that's easy (-:! BTW, it's a 1979 750, but I put an electronic ignition in and swapped out the OEM coils for the green Dynas.

              Thanks everyone for your responses!

              Rick
              measure the resistance if your wires to confirm they or or one are bad.if not it might be a one of the secondary connections. You never said say kind of wires you had.

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              • ryonker

                #8
                I will check the wires. I think I had to make them from bulk wire after I switched out my OEM coils but that was 4 or 5 years ago. Any suggestions for plug wire replacements? I

                Comment

                • Guest

                  #9
                  No riding until your problem is fixed.

                  Comment

                  • Buffalo Bill
                    Forum Guru
                    Past Site Supporter
                    Super Site Supporter
                    • Jun 2008
                    • 6004
                    • New Buffalo, Michigan 49117

                    #10
                    Hope this ain't the result of monkey business.
                    Like, if you want a new sport bike, just buy one.
                    1982 GS1100G-
                    1990 GSX750/1127
                    1987 Honda CBR600F Hurricane
                    1985 Kawasaki GPz750

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