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Power Hiccups and Bad Fuse Holder?

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    Power Hiccups and Bad Fuse Holder?

    Haven't had to do anything to the bike except fuel it up for months. I was enjoying one of the last days of ride-able weather over New Years, when this happened.

    After about an hour's riding, the bike began acting up few blocks from home. The engine would miss and sputter, then surge and backfire.

    While idling, I checked the plug wire connections, to see if any had worked off the plugs, gotten loose, etc. The No. 3 wire gave me a shock through my glove.

    At one point after surging and failing from a stop, the bike died and I coasted to the side. Checked things out, thinking that the fuse had blown (because everything died, including lights) but she started right back up.

    I limped the bike home. Turned the key again in the garage, lights came up, but when I hit the starter, the electrics popped like a blown fuse. This time, however, she did not start again. So I checked the two fuses (one main, one for ignition relay). The main fuse was fine. The relay fuse also looked fine, but I replaced it just in case. Since the starter seemed to blow things, the relay fuse seemed more suspect.

    Bike started up again. Shut her down to hunt down a short. Everything looked solid. No burnt connections or cracked wire insulation that I could see. When I started her up again, lights come up, but the starter kills the electrics dead. Another blown fuse, I thought.

    This shifted my attention back to the fuse holder for the relay. I did the relay several months ago, so the holder is new. It is an inline fuse holder for a glass tube fuse that uses a spring to secure the fuse itself. When I pulled the fuse out, it looked intact. Put the back together and the bike starts. Poke around to hunt the problem. Try the bike again - starter kills the electrics. But the fuse is intact. Basically, I think the holder is breaking connection without blowing the fuse. When I jostled the fuse holder to look for wire problems, it primed the fuse to disengage (but not blow?)

    I have pulled that fuse holder and replaced it with a blade version. I also double-checked the surrounding wires and connections for any possible gaps in insulation. Nothing stood out, but I taped up some possible tiny insulation cracks (though they might have been smudges).

    Basically, my relay fuse seems to have been "half-blowing" such that drawing power through it (via the starter) would cause it to break connection but not burn the fuse itself. Can that even happen? Other than cracking the fuse, I know of no other way for power along the line to cause the line to break connection. But the fuses are not blowing. Has anyone had these symptoms? Is it just a dodgy holder?

    My fear is that the surge/sputter will happen in a turn or something, which would suck pretty hard. So I am very open to ideas on how to root out this odd electrical item.

    #2
    " When I started her up again, lights come up, but the starter kills the electrics dead. Another blown fuse, I thought."

    Disconnect the big wire from solenoid to starter motor-then push starter button, do electrics go dead now? How big is this "relay" fuse? and is it in series with another fuse other than main fuse?
    1981 gs650L

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

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      #3
      Originally posted by tom203 View Post
      " When I started her up again, lights come up, but the starter kills the electrics dead. Another blown fuse, I thought."

      Disconnect the big wire from solenoid to starter motor-then push starter button, do electrics go dead now? How big is this "relay" fuse? and is it in series with another fuse other than main fuse?
      I'll check out the solenoid link.

      The two fuses are:

      15 AMP main fuse for the entire bike (1978 didn't have separate fuses)
      15 AMP fuse for the line powering the relay, because it connects directly to the battery, bypassing the main fuse.

      The fuses are not in series.

      Comment


        #4
        I'd suspect that you have a bad relay, so I'd replace it and doublecheck the wiring. The starter motor draw drops the system voltage and could cause the relay to open its contacts. But randomly cutting out while you're cruising seems to suggest the relay is failing.
        1981 gs650L

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

        Comment

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