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    Unidentified Carb Part

    Hello,
    I have apart a set of '77 gs750 carbs. On the bottom faceing downward there is a tapered screw with an o-ring that is external and can be accessed without pulling the bowl.
    It kinda looks like a large air/fuel mixture screw. I called my dealer and he siad there is no such thing according to his computer.
    Any ideas? I suppose the PO might have swapped out the carbs for a different set.
    Thanks
    Shawn Alexander

    #2
    It's a fuel screw, used for finetuning in the factory. Haynes manual say's not to touch it (but we do it anyway :twisted: ).

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      #3
      Robin
      These fuel screws where all set at 1 turn out, do you know if this is correct? 2 need to be replaced, one of them is filed down and much shorter and the other was seated too tight and has a nice little ring indented in the tip.
      Does anyone know what the part number would be for these? My dealer is not too helpful on this one.
      thanks
      Shawn Alexander

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        #4
        The 1 that is much shorter was broken off in the hole. Make sure that the tip is not still in the hole and that the taper in the carb body is not damaged. 1 turn out sounds like it's in the neighborhood of being correct, but these needle settings are very sensitive. You were supposed to have springs on the needles too.

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          #5
          Yip, one of the tips was still in the carb but i was able to remove it with no problem. Unfortunatly one hole is drilled out slightly bigger so i may be sol anyway. I have learned that these screws are not and never where availible from suzuki so it looks like i will be looking for a bank of carbs.
          Thanks for your input
          shawn

          Comment


            #6
            Just be sure you get carbs with the same pilot circuit design.
            The '77 to '79 VM carbs look the same. Your '77 carbs should have 2 pilot circuit passages to the main bore. One leads straight to the main bore, the other also leads to the main bore but is regulated by the pilot screw.
            So when you look down into the carb, you should have 2 tiny holes.
            Because of stricter emissions standards, some '79's were equipped with carbs that had only 1 hole. These carbs also had blunt tipped pilot screws, they did'nt do anything. These carbs run leaner at idle/low rpm's.
            So make sure you see 2 holes.
            And on the seventh day,after resting from all that he had done,God went for a ride on his GS!
            Upon seeing that it was good, he went out again on his ZX14! But just a little bit faster!

            Comment


              #7
              I have two of them from 79 850 if that will help PM me

              Comment


                #8
                Suzuki hides this screw on all of their drawings of the carbs...its a real pain.

                its called the fuel pilot screw, or something along those lines. it helps the bike idle and off idle throttle till about 3500-4000 RPM. i would suggest trying 1 turn out on it...BE VERY CAREFUL TIGHTENING IT DOWN. do not break the tip off in the carb body like i did.

                your best aid in tuning these screws is the plug color...

                Comment


                  #9
                  I found a complete set of carbs so instead of messing with this set (being one hole was drilled out) im gonna go with another set.
                  Thanks guy's for all your input, this is a great place for gs'ers
                  Shawn

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