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    VM carb throttle adjuster problem.

    I'm really new to VM carbs on GS1000S's as I have only ever had CV carbs.

    In the centre directly underneath the middle of the carbs is a round knob which I take is the throttle stop adjuster. So what does it do??

    I've turned this knob hoping to bring the tickover down from 1500rpm to about 1100 but to no availe. It doesn't change the slack on the throttle cables. It doesn't lift the revs so what is it doing?

    All I wanted was to bring the tickover down to 1100rpm.

    I'I re-read the manual but I am guessing that something is not connected correctly here.

    Any suggestions before the carbs come out onto the bench.

    Suzuki mad

    #2
    The knob is for idle speed adjustment. The throttle cables may be in need of adjustment also, if the knob does nothing. Ray
    "Nobody goes there anymore, it's too crowded" -Yogi Berra
    GS Valve Shim Club http://www.thegsresources.com/_forum...d.php?t=122394
    1978 GS1000EC Back home with DJ
    1979 GS1000SN The new hope
    1986 VFR700F2 Recycled

    Comment


      #3
      Something is misadjusted . . . the VM GS1000 carbs use a push pull throttle cable set up. The slack in the throttle cables can be adjusted in two places. Below the throttle grip housing were the cables exit you will find a couple of jam nuts that adjust the cable slack. The second place is were the two cables attach to the carbs.

      Since you stated the round knob has no effect on the engine idle this would infer the the throttle cables are misadjusted (too tight) and one of them ( likely the pull side ) is holding the slides open.

      Take off the Gas tank and loosen up the jam nuts underneath the throttle grip so they have no effect on the slide position. Then adjust the cables were they attach to the carbs. The pull cable should have a slight amount of slack.
      Steve

      1979 GS1000E (45 Yrs), 1981 GPz550 (11 Yrs)

      Comment


        #4
        Good advice above - if your revs aren't dropping it's cable adjustment. I'd also check that the adjuster was actually sitting in the threads - there's a lot (an excess?) of adjustment on it and I would have thought if you'd wound it fully in your bike would be revving its head off. (It's a normal RH thread by the way).
        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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          #5
          Thanks guy's.

          So thats why when you rev it it drops back to about 1700 then slowly goes to 1500 but its an instant rev up when you touch the throttle. For what your saying my guess would be that the pull side is tight.

          I can't adjust the throttle ends as the lock nuts are seized solid. Rust.

          Suzuki mad

          Is

          Comment


            #6
            Pull the tank and adjust the cables where they run into carbs.

            Use some Seafoam spray (do you have that across the pond) on the throttle side. Give it a spritz daily - it will actually reduce the rust
            1978 GS 1000 (since new)
            1979 GS 1000 (The Fridge, superbike replica project)
            1978 GS 1000 (parts)
            1981 GS 850 (anyone want a project?)
            1981 GPZ 550 (backroad screamer)
            1970 450 Mk IIID (THUMP!)
            2007 DRz 400S
            1999 ATK 490ES
            1994 DR 350SES

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              #7
              High idle could also be a vacuum leak.
              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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