Knock sound during start

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  • NashGS83
    • Feb 2026

    #1

    Knock sound during start

    Have an 83 GS1100G, within the past few weeks when I push the electric start button a loud single knock sound comes from the bottom left side of the engine...sounds like a hammer hitting a metal plate. I let off the button and try again, sometimes it will knock again and start, sometimes it won't knock and start. Doesn't happen every time but it seems to be getting worse. I haven't been able to find any posts with a similar issue. Don't know if I'm damaging anything by continuing to ride the bike. Any comments and suggestions would be greatly appreciated.
  • hampshirehog
    Forum LongTimer
    Past Site Supporter
    • Oct 2007
    • 12675
    • Hampshire. UK

    #2
    Does it sound more like a clack? If so that's a classic sign of a starter clutch problem.
    79 GS1000S
    79 GS1000S (another one)
    80 GSX750
    80 GS550
    80 CB650 cafe racer
    75 PC50 - the one with OHV and pedals...
    75 TS100 - being ridden (suicidally) by my father

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    • Guest

      #3
      Starter clutch
      It also happens when your battery is low and not turning your starter as quickly as it should.

      Comment

      • willie
        Forum Sage
        Past Site Supporter
        • Mar 2006
        • 1836
        • Kingsport, TN

        #4
        I've been through the same thing with an 1100G I had awhile back. If I remember correctly, I wound up having to buy a stator puller to gain access to the starter clutch. I found one or two of the springs were shot, the pins were worn out and the cup everything resides in was deformed. I strongly suggest that you tear into it now before it gets worse. Kinda like a cavity in a tooth in that its not going to get any better.
        Good luck.
        Willie
        Common sense has become so uncommon that I consider it a super power.


        Present Stable includes:
        '74 GT750 Resto-mod I've owned since '79
        '83 GS1100E (The best E I've ever enjoyed, Joe Nardy's former bike)
        '82 GS1100G Resto project

        Comment

        • NashGS83

          #5
          The sound can be described as a clack. Checked the battery voltage but don't know what it should be to start...was 13.1V, 12.8 when I turn the key ON, 13.4V at 4500 rpm. Btw, is the headlight supposed to be on before the engine is started? Found two burnt wires and a connector before this "clack" problem started and the headlight did not turn on without the engine started. Fixed the burnt wires and connector and now the headlight and front turn signal lights turn on when the key is turned to the ON position prior to starting. Then the "clack" problem started...is the headlight and turn signal lights drawing too much voltage to start? Do I need to fix the wiring so the headlight does turn on prior to the engine running? Then check to see if I still have a clack or just go ahead and pull the starter clutch?

          Comment

          • Guest

            #6
            Unless someone put in a headlight relay of some kind the headlight would of always came on with the ignition switch.
            The burnt wire is more than likely a stator wire that is looped and should be bypassed by connecting the R/R directly to the stator. It used to go to the headlight on/off switch to cut a leg out of the charging when the light was off but that was discontinued here in the states for visibility reasons.

            Comment

            • Guest

              #7
              Inspect the starter clutch - that clack is a classic symptom of a worn/broken starter clutch. (as hampshirehog said)...

              Do it sooner rather than later - bad things happen if that starter clutch decides to self-destruct.

              Gotta pull the stator rotor off the crank to get to it, lots of posts here about that. It can be a hellish job, & a surprisingly easy one - never know until you open it up.

              Comment

              • tkent02
                Forum LongTimer
                Past Site Supporter
                • Jan 2006
                • 35571
                • Near South Park

                #8
                Have you guys ever heard of a starter clutch having problems on the smaller bikes? (550)
                http://img.photobucket.com/albums/v5...tatesMap-1.jpg

                Life is too short to ride an L.

                Comment

                • NashGS83

                  #9
                  Thanks for the replies...bought a 35 x 1.5, 3" deep, RH external rotor remover yesterday. Will inspect the starter clutch as suggested when the puller arrives.

                  Comment

                  • Guest

                    #10
                    Originally posted by tkent02
                    Have you guys ever heard of a starter clutch having problems on the smaller bikes? (550)
                    I've had a couple of 550's and although I didn't have them long, I never experienced any issues with the starter cluch on either of them...

                    Comment

                    • Guest

                      #11
                      Originally posted by NashGS83
                      Thanks for the replies...bought a 35 x 1.5, 3" deep, RH external rotor remover yesterday. Will inspect the starter clutch as suggested when the puller arrives.
                      When I opened up my 1100E, the rotor practically fell off in my hands. You never know what you'll find I guess...

                      Good luck

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