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    Melted power wire?

    I just upgraded my 78 GS750 to a SH775 R/R a week or so ago and today I broke down. I don't think these really don't have anything to do with each other but figured I should mention it. I've put about 80ish miles on the bike since the R/R install with no issues. After riding about 4 or 5 miles today, I was accelerating at a rather brisk pace and lost all electrical power and the bike shut off. I figured I had blown the fuse on the main power wire and I was correct. I did not have a screwdriver with me to pull the side cover off so the best I could do was pull off the fuse holder and connect the harness side of the power wire to the battery. I had thought the fuse was very old (I have never replaced it) and that it just popped from being old. Anyway, I loosened the + terminal and clamped the end of the power wire into it to limp it the few miles back to my house to make a repair. At his point I hadn't turned the key on and was putting my gear back on. The wire had been connected for a minute or two and all of a sudden the wire just completely melted itself. I'm not sure how far up the harness it went but I would like to cut the harness apart and replace the whole length of wire just to be safe. I'm fairly well versed in electrical stuff but I guess my question is what would cause this with the key being off? After I got it home I hooked the wire back up just to see (with a fuse this time) and it popped it immediatly, again with the key off.

    I have upgraded to the SH775 R/R and I have LED turn signals and a Wideband O2 gauge on the bike, everything else is stock. I should mention that I wired the R/R with its own 15amp fuse to the starter solenoid to clean up the wiring under the seat and the O2 is wired with a relay to the solenoid as well. I have also made a ground wire from the battery to one of the bolts for the starter relay and all the other loose grounds are connected at that common point.
    The current garage:
    1978 GS750
    1975 GT750M
    1984 CB700SC
    1982 XJ650 Seca Turbo
    1975 RD250 - 350 conversion

    #2
    Sounds like you have a dead short somewhere; one of the always hot power wires is shorted to ground. I'd trace all your mods and look at those circuits first.
    Ed

    To measure is to know.

    Mikuni O-ring Kits For Sale...https://www.thegsresources.com/_foru...ts#post1703182

    Top Newbie Mistakes thread...http://www.thegsresources.com/_forum...d.php?t=171846

    Carb rebuild tutorial...https://gsarchive.bwringer.com/mtsac...d_Tutorial.pdf

    KZ750E Rebuild Thread...http://www.thegsresources.com/_forum...0-Resurrection

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      #3
      Found the problem, the wires from the old rectifier must have fallen below the battery box and I didn't see them to tape them up during the install. At least I think that's the problem. I'm really kicking myself now do you think there's any damage to the stator or r/r. I think I'll get away with just replacing the short section of wire that burned
      The current garage:
      1978 GS750
      1975 GT750M
      1984 CB700SC
      1982 XJ650 Seca Turbo
      1975 RD250 - 350 conversion

      Comment


        #4
        Simple charging system test is the run the bike at 5000 rpm and check voltage at the battery - should be about 14.5 VDC.
        Ed

        To measure is to know.

        Mikuni O-ring Kits For Sale...https://www.thegsresources.com/_foru...ts#post1703182

        Top Newbie Mistakes thread...http://www.thegsresources.com/_forum...d.php?t=171846

        Carb rebuild tutorial...https://gsarchive.bwringer.com/mtsac...d_Tutorial.pdf

        KZ750E Rebuild Thread...http://www.thegsresources.com/_forum...0-Resurrection

        Comment

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