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Rebuilding Carbs - Pilot Fuel Screw

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    Rebuilding Carbs - Pilot Fuel Screw

    I finally started installing the new parts on the '78 GS750 carbs tonight. I made it to the third piece (Pilot Fuel Screw) before thinking it might be best to ask for advice. This little rascal has quite the stiff spring and as I attempted to get the threads started the screw was moving from side to side and I saw a real opportunity for a cross-threading incident. This would not be good thing!

    Can any of the experienced carb rebuilders offer suggestions on how to get this piece properly threaded in the carb body?

    Thanks,
    rickt

    #2
    I just did a set of carbs on a '79 550 and did not think that the spring was all that stiff. Besides, I could get a couple of turns on the screw before the spring started to compress. Took another 6 or 7 turns to seat them, then backed them out 2 turns.

    Check the screws without the springs. Make sure they are not cross-threaded, and count the turns from just-engaged to lightly-seated. That way the tension of the spring will not confuse you.


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    Comment


      #3
      Thanks Steve. On my carbs the screw is not even close to the threads on the carb body when the spring begins to compress. Just measured it - with no spring on the screw, there is about 5 mm of screw head showing when the threads first start to engage. With the spring on the screw, there is 15 mm of screw showing when the spring starts to compress. So, I will have to push that bugger in 10 mm against the spring just to get the threads started. I thought maybe I was using the wrong spring from the rebuild kit (Keyster), but when I tried the original that was removed from from this carb, the result was the same.

      Maybe it will require the brute force approach?

      rickt

      Comment


        #4
        Check and make sure the old spring is out.
        1983 GS 1100E w/ 1230 kit, .340 lift Web Cams, Ape heavy duty valve springs, 83 1100 head with 1.5mm oversized SS intake valves, 1150 crank, Vance and Hines 1150 SuperHub, Star Racing high volume oil pump gears, 36mm carebs Dynojet stage 3 jet kit, Posplayr's SSPB, Progressive rear shocks and fork springs, Dyna 2000, Dynatek green coils and Vance & Hines 4-1 exhaust.
        1985 GS1150ES stock with 85 Red E bodywork.

        Comment


          #5
          Bench Sync

          While we are on this subject can someone post the bench sync procedure for me. I have a '81 850GL
          Thanks for your help

          Comment


            #6
            It should not be hard to install. You either have the wrong fuel screw or wrong spring

            Comment


              #7
              A New Discovery

              My immediate thought after trying to compress the spring on the pilot fuel screw far enough to get the thing threaded was that I had the wrong screw and/or the wrong spring. So, I pulled out the screw and spring that was in the carb when I disassembled in. This screw and spring were identical with the ones in the rebuilding kit. Inspecting the three other carbs convinced me that I had the right pieces.

              Tonight I discovered yet a new problem. Apparently the sharp tip of the screw in three of the four carbs broke off when I disassembled them for cleaning. And yes, all four were cleaned thoroughly by tank soaking and spray. No parts were left in the carb bodies. I was following Paul Musser's rebuilding instructions and turned each of the screws in to it was seated in order to set it the same when reassembling. Looks like I tightened them too much and wedged the needle point into the carb body. When I tried to remove them, and serveral were badly corroded, they broke off leaving the pointed end inside.

              So, with this new problem to solve, I am seeking suggestions on how to remove the small pointed end of the pilot fuel screw. In two carbs I can actually see the pointed end protruding through the carb body.

              Any ideas???

              rickt

              Comment


                #8
                I would gently tap it out.
                1983 GS 1100E w/ 1230 kit, .340 lift Web Cams, Ape heavy duty valve springs, 83 1100 head with 1.5mm oversized SS intake valves, 1150 crank, Vance and Hines 1150 SuperHub, Star Racing high volume oil pump gears, 36mm carebs Dynojet stage 3 jet kit, Posplayr's SSPB, Progressive rear shocks and fork springs, Dyna 2000, Dynatek green coils and Vance & Hines 4-1 exhaust.
                1985 GS1150ES stock with 85 Red E bodywork.

                Comment


                  #9
                  Unfortunately, one can\not get a straight shot at the protruding tip. My efforts to tap it out resulted in the tip getting blunt. This will probably increase the difficultly of removal. I'm beginning to think that I will need to take them to a machinest and have the tips drilled out. Does anyone know the diameter of the tiny hole in the carb body (or where I can find it)?

                  rickt

                  Comment


                    #10
                    Check this: http://www.thegsresources.com/_forum...ght=broken+tip

                    Is this what you're talking bout?

                    Comment


                      #11
                      Thank You!

                      Yes, this is exactly my problem - well one of my problems. I toyed with the idea of trying to push it out with a sharp object, but I was afraid of reaming out the opening. I'll sharpen the awl and give it a try. I think that one or two of my carbs have the end of the screw below the surface of the carb body. If I knew the diameter of the opening, I would try to fabricate a small tool - maybe with very stiff stainless wire.

                      Thanks again for the reference.

                      rickt

                      Comment

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