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  • Harley 9B carb help needed.

    After years of problem free operation my 1913 9B has started to spray or 'pulse' fuel from the bottom of the float bowl (main nozzle). After inspection I replaced the float which was cork and had deteriorated and then re-assembled it but the problem remains. I have checked the carb settings, all the usual stuff. I'm sure the problem must be the carb but the pulse relates to the stroke so I also rechecked the inlet timing. No leaks, easy starting and the motor runs great but the spray is a problem. The only recent alteration has been installing a new throttle shaft. Can anyone point me in the right direction please.
    Thanks.
    Ian Biddle
    www.f-head.com

  • #2
    What kind of replacement float did you install, Ian?

    There's some HX boat anchors out there, both brass and molded.

    The next thing I would inspect would naturally be the airvalve.

    ....Cotten
    Last edited by T. Cotten; 09-22-2019, 09:39 AM.
    AMCA #776
    Dumpster Diver's Motto: Seek,... and Ye Shall Find!

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    • #3
      I used a moulded Nitrofill (Nitrile) type. They seem good and are what I have used on my other teensters.
      The Schebler manual also suggests the air valve. The stem might be loose in the adjuster but I wondered if I am missing anything more obvious before I tackle the valve.
      Thanks for your advice.
      Ian Biddle
      www.f-head.com

      Comment


      • #4
        Did you weigh your new float, Ian?

        Or at least compare them, hand to hand?

        (And beware of swelling in USA fuels...)

        ....Cotten
        PS: There's been at least thirteen different Nitrophyls, not counting the counterfeits.
        Only the very last has proven itself against P4gas, and nobody (except auto manufacturers) paid the royalty to mold it.
        Last edited by T. Cotten; 09-22-2019, 02:04 PM.
        AMCA #776
        Dumpster Diver's Motto: Seek,... and Ye Shall Find!

        Comment


        • #5
          Hi Cotten, no I did not weigh the two floats but the old cork and the new Nitrile floats are similar in size.
          There is plenty of clearance in the bowl, no binding and good movement when fuel rises.
          The new float has only been in a few days so no swelling yet! I presumed Nitrile would not swell.
          I was not aware this was such an issue.
          Is your suggestion that the density of the float might mean there is still too much flow of fuel?
          Thanks.
          Ian Biddle
          www.f-head.com

          Comment


          • #6
            Please consider, Ian,...

            If the same size of float weighs three times as much.

            T'aint nothing "nitrile", no matter what you bought... (Since the proprietor of the original Nitrophyl won't protect their name, its become "generic".)

            Stay away from P4gas, or it won't stay the same size either.

            ....Cotten
            AMCA #776
            Dumpster Diver's Motto: Seek,... and Ye Shall Find!

            Comment


            • #7
              Thanks again, I'll get the weighing scales out tomorrow.
              Ian Biddle
              www.f-head.com

              Comment


              • #8
                The old cork float was 2.5 grams and the Nitrile was 5 grams. The depth of the latter was also much deeper (18mm v 12.5mm). I turned the Nitrile one down in size removing 2 grams.
                After refitting I still had the same problem. Now I will look at the air valve.
                Ian Biddle
                www.f-head.com

                Comment


                • #9
                  Buoyancy, Ian,..

                  Isn't just about weight, but also volume.

                  Making the float lighter doesn't help if it makes it smaller.

                  A buoyant float can be set to book spec, saving a lot of tail-chasing.

                  ....Cotten
                  PS: Please note in this jar of fuel are four different 'nitrophyl' Linkert replacements, including the one on the bottom
                  Making it smaller won't make it float.
                  Attached Files
                  Last edited by T. Cotten; 09-24-2019, 08:55 AM.
                  AMCA #776
                  Dumpster Diver's Motto: Seek,... and Ye Shall Find!

                  Comment


                  • #10
                    Ian, buy one of Tom's Durable lifetime guarantee floats and the float variable will be removed from the equation.
                    Steve Swan

                    27JD 11090 Restored
                    https://www.youtube.com/watch?v=ClUPIOo7-o8
                    https://www.youtube.com/watch?v=LtuptEAlU30

                    27JD 13514 aka "Frank"
                    https://forum.antiquemotorcycle.org/...n-Project-SWAN
                    https://www.youtube.com/watch?v=hNRB...nnel=steveswan

                    https://www.youtube.com/watch?v=RSDeuTqD9Ks
                    https://www.youtube.com/watch?v=bwlIsZKmsTY

                    Comment


                    • #11
                      Thanks Steve!

                      Lifetime as long as I'm alive.

                      But what's my guarantee if the material goes extinct?

                      (Where's my trolls when I need them for a punchline...)

                      ....Cotten
                      PS: I finally found my pic of a molded H float. Miy production is appears porous, because it is machined from pre-cast boards.
                      Attached Files
                      Last edited by T. Cotten; 09-24-2019, 10:58 AM.
                      AMCA #776
                      Dumpster Diver's Motto: Seek,... and Ye Shall Find!

                      Comment


                      • #12
                        Where do I get one of these floats?
                        Ian Biddle
                        www.f-head.com

                        Comment


                        • #13
                          and are the float lever, valve, etc also available?
                          It might make sense to change all the parts if possible.
                          Thanks again Tom & Steve.
                          Ian Biddle
                          www.f-head.com

                          Comment


                          • #14
                            You can always email me direct at liberty@npoint.net, Ian!

                            I don't change out floatlevers, I die-press the pin bores tight on a 3/32" drill shank, and then ream out to fit the fresh pin.
                            This slightly widens it, allowing to be centered by filing only one side.

                            But the floatvalve needle itself is certainly best replaced, along with re-cutting and burnishing the seat of course.
                            (Unfortunately, my commissioned inventory of Monel-tipped needles are reserved for my services, and I have no experience with ebay brass and stainless offerings.)

                            Especially with this early stuff, oftener its better to fix what you have than buy a funky reproduction.

                            Happy to help if I can,

                            ....Cotten
                            PS: Oftener is a harley word, like on their aircleaners.
                            Last edited by T. Cotten; 09-25-2019, 01:24 PM.
                            AMCA #776
                            Dumpster Diver's Motto: Seek,... and Ye Shall Find!

                            Comment


                            • #15
                              Originally posted by Ian Biddle View Post
                              Where do I get one of these floats?
                              from Tom Cotten
                              Steve Swan

                              27JD 11090 Restored
                              https://www.youtube.com/watch?v=ClUPIOo7-o8
                              https://www.youtube.com/watch?v=LtuptEAlU30

                              27JD 13514 aka "Frank"
                              https://forum.antiquemotorcycle.org/...n-Project-SWAN
                              https://www.youtube.com/watch?v=hNRB...nnel=steveswan

                              https://www.youtube.com/watch?v=RSDeuTqD9Ks
                              https://www.youtube.com/watch?v=bwlIsZKmsTY

                              Comment

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