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    Fuel tap mystery

    hey all,
    My bike had a bastardised fuel tap off a mower mounted on it when I acquired it recently, so I bought a new vacuum tap and after fitting it, realised that the handle isnt included in the deal. I checked assorted fiches and the handle [with the round indicator hole] is nowhere to be found.
    Anyone lead me in the right direction please?????
    AlIMG_3727.jpg
    Last edited by Guest; 10-14-2018, 05:08 PM.

    #2
    heres some photos just after I acquired the bikeIMG_3729.jpg

    Comment


      #3
      Hard to tell from the pic but it sounds like you might have the "dreaded 1980 petcock".
      Steve explains the operation in this thread.


      Low mileage bike you have. Is that a stainless MotoGP exhaust?
      2@ \'78 GS1000

      Comment


        #4
        Yep, even though you have given us only one clue to what bike you have (a 16-valve 1100, either '80 or '81),
        the petcock in use tells me that it's an '80.

        There is no "handle" for that petcock, just a screwdriver slot.

        And, ... are you ready for this? There is NO RESERVE function.

        Hope your fuel gauge works well.

        .
        sigpic
        mine: 2000 Honda GoldWing GL1500SE and 1980 GS850G'K' "Junior"
        hers: 1982 GS850GL - "Angel" and 1969 Suzuki T250 Scrambler
        #1 son: 1986 Yamaha Venture Royale 1300 and 1982 GS650GL "Rat Bagger"
        #2 son: 1980 GS1000G
        Family Portrait
        Siblings and Spouses
        Mom's first ride
        Want a copy of my valve adjust spreadsheet for your 2-valve per cylinder engine? Send me an e-mail request (not a PM)
        (Click on my username in the upper-left corner for e-mail info.)

        Comment


          #5
          fuel tap woes

          Originally posted by Steve View Post
          Yep, even though you have given us only one clue to what bike you have (a 16-valve 1100, either '80 or '81),
          the petcock in use tells me that it's an '80.

          There is no "handle" for that petcock, just a screwdriver slot.

          And, ... are you ready for this? There is NO RESERVE function.

          Hope your fuel gauge works well.

          .
          yes indeed its a GS1100 4 valver 1980....
          So I fitted the new tap and now the bike runs on the prime setting just long enough to drain the bowls and then it stops......
          Wait a few minutes and it starts again, runs for a minute or so then stops....bugger me.......
          Ill put a fuel line on the tank and see what happens when I just let fuel run with the tap on prime and see how long it goes before something happens.....gggrrrr.......

          Comment


            #6
            Originally posted by steve murdoch View Post
            Hard to tell from the pic but it sounds like you might have the "dreaded 1980 petcock".
            Steve explains the operation in this thread.


            Low mileage bike you have. Is that a stainless MotoGP exhaust?
            Actually I thought it was 47000km, not 4700.............ha!
            Does anyone know of a simple on-off option rather than the silly vacuum system? I have seen some taps that have a clip-on handle, but every bike I checked at the local wreckers was the same as mine. It must have been a different model perhaps.

            Comment


              #7
              Think what you will of the "silly vacuum system", but I prefer it. I have used one for so long, I would forget to turn one on and off, as necessary.

              Now, if you have grown up with nothing but on/off valves on dirt bikes and other older bikes, you would be accustomed to turning it. One often-recommended valve is made by Pingle. Be careful when shopping, as your petcock has different bolt spacing.

              .
              sigpic
              mine: 2000 Honda GoldWing GL1500SE and 1980 GS850G'K' "Junior"
              hers: 1982 GS850GL - "Angel" and 1969 Suzuki T250 Scrambler
              #1 son: 1986 Yamaha Venture Royale 1300 and 1982 GS650GL "Rat Bagger"
              #2 son: 1980 GS1000G
              Family Portrait
              Siblings and Spouses
              Mom's first ride
              Want a copy of my valve adjust spreadsheet for your 2-valve per cylinder engine? Send me an e-mail request (not a PM)
              (Click on my username in the upper-left corner for e-mail info.)

              Comment


                #8
                Originally posted by abgill@telus.net View Post
                Does anyone know of a simple on-off option rather than the silly vacuum system?
                Originally posted by Steve View Post
                One often-recommended valve is made by Pingle. Be careful when shopping, as your petcock has different bolt spacing.
                A few words about the Pingels. Yes they work, and they look very nice. But having had them on two different GS bikes, (one I still have), a few words of caution.

                1. They actually cost the same or more than stock...Around $100

                2. You will forget to turn it off one day and have a case full of gas...happens to everyone I know that put one on.

                3. After 8-10 years they WILL start to leak. Stock should go for 20-30 years or so. (Supposedly, you can send the Pingle in for a rebuild, but I don't know for sure.)

                To be fair, I just put a new one on my GS1100E, it works fine, and looks great.
                Bob T. ~~ Play the GSR weekly photo game: Pic of Week Game
                '83 GS1100E ~ '24 Triumph Speed 400 ~ '01 TRIUMPH TT600 ~ '67 HONDA CUB

                Comment


                  #9
                  Even on prime, that petcock needs a bump of vacuum to get it open. The difference is, when the barrel is turned to prime, it blocks off an air bleed and the diaphragm will theoretically hold open after after the vacuum source is removed (at least for a while); and in the run position, a small air bleed is exposed that will let the spring push the diaphragm closed after the vacuum source (like an running engine) is removed.
                  Did you get an aftermarket or OEM replacement?
                  I bought an aftermarket one years ago that gave me nothing but headaches.... I eventuall replaced the spring under the diaphragm with the OEM spring from the old petcock.... kinda worked.... but would still decide to flood the crankcase with fuel at least once a year. Usually after a fresh oil change.
                  Now I have a 5/16 inline fuel valve.
                  Buying a cheap petcock over the OEM was some of the worst money I never spent.
                  -1980 GS1100 LT
                  -1975 Honda cb750K
                  -1972 Honda cl175
                  - Currently presiding over a 1970 T500

                  Comment


                    #10
                    The factory service manual (available for free download from Basscliff's website) details how the factory petcock functions. As mentioned already, in order for "prime" to function there needs to be some vacuum to initially pull it open, then a check valve embedded into the back cover holds it open.

                    I also bought an aftermarket petcock, which incidentally looked identical to the OEM petcock, only the check valve never worked. Sprang for a new OEM petcock and all was good after that. If there is only intermittent fuel flow that could be a petcock issue or possibly a venting issue (through the cap). I'd check all possibilities just to be safe.
                    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


                      #11
                      Its a real Suzuki petcock

                      Originally posted by Nessism View Post
                      The factory service manual (available for free download from Basscliff's website) details how the factory petcock functions. As mentioned already, in order for "prime" to function there needs to be some vacuum to initially pull it open, then a check valve embedded into the back cover holds it open.

                      I also bought an aftermarket petcock, which incidentally looked identical to the OEM petcock, only the check valve never worked. Sprang for a new OEM petcock and all was good after that. If there is only intermittent fuel flow that could be a petcock issue or possibly a venting issue (through the cap). I'd check all possibilities just to be safe.
                      YES its a real Suzuki petcock, $150 at the Suzuki dealer. Im looking at fuel flow this morning. Im also contemplating pulling the carbs......

                      Comment


                        #12
                        so does the last digit on the speedometer read in KM's or 1/10ths of km, so the mileage shown at 4507.7 would either be forty five thousand and seventy seven, or is it forty five hundred and seven and seven tenths? Just asking. The bike certainly appears to be well past 4500km, thats for sure.......

                        Comment


                          #13
                          Originally posted by abgill@telus.net View Post
                          so does the last digit on the speedometer read in KM's or 1/10ths of km, ...
                          The picture you posted earlier shows four thousand, five hundred twenty five and seven tenths kilometers.

                          How much have you ridden since that picture?



                          .
                          sigpic
                          mine: 2000 Honda GoldWing GL1500SE and 1980 GS850G'K' "Junior"
                          hers: 1982 GS850GL - "Angel" and 1969 Suzuki T250 Scrambler
                          #1 son: 1986 Yamaha Venture Royale 1300 and 1982 GS650GL "Rat Bagger"
                          #2 son: 1980 GS1000G
                          Family Portrait
                          Siblings and Spouses
                          Mom's first ride
                          Want a copy of my valve adjust spreadsheet for your 2-valve per cylinder engine? Send me an e-mail request (not a PM)
                          (Click on my username in the upper-left corner for e-mail info.)

                          Comment


                            #14
                            Originally posted by Steve View Post
                            The picture you posted earlier shows four thousand, five hundred twenty five and seven tenths kilometers.

                            How much have you ridden since that picture?



                            .
                            my apologies, thats the numbers on the speedometer....I cant get it to run so no extra km's....
                            Boy it sure looks and feels like a 45000KM bike, or the previous owners were just animals........
                            It was a 'barn find' so I guess ultimately nothing surprises me......
                            4525.7 km would sure be nicer than 45257 km for sure.
                            Al

                            Comment


                              #15
                              I have to get back at it before the snow flies, but Im finding it hard to park my 71 CB750 to work on the GS....
                              What a terrible first world problem to have....!!!
                              IMG_2078.jpg

                              Comment

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