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  • Fast Idle or Hard Starting

    I'm sort of stuck between a rock and a hard place. If I lower the idle to a reasonable RPM I cannot get the bike started easily. If I run the idle at 1500, it starts easily with minimal choke. I'm at two turns out on the idle mix screws. More turns out doesn't make any obvious difference. Any suggestions? I have a K&N in a stock airbox,Jardine 4in1 exhaust, 145 mains,42.5 idle jets,floats are at 26mm, bike is a '79' xs1100 SF, carbs are synced, and the needles are at the middle notch. I've got a flat spot just off idle. When I start off of idle it's like it takes a second catch up and get enough fuel to get going. Once I get past about 2500 RPM's it really takes off. Plugs look good and mileage is about 35 to37 MPG. Now what, do I need to go to a 45 idle jet?
    1979XS1100SF
    K&N's and drilled airbox
    Jardine 4in1
    Dunlop Elite 3's
    JBM slide diaphragms
    142.5 main jets
    45 pilot jets
    T.C.'s fusebox & SOFA
    750/850 FD mod.
    XV 920 Needle Mod.
    Mike's XS plastic floats set at 26mm
    Venture Cam Chain Tensioner

  • #2
    flat spot

    Don't know about the jets, but flat spot or hesitation off idle usually means lean idle mixture.
    2H7 (79) owned since '89
    3H3 owned since '06

    "If it ain't broke, modify it"

    Comment


    • #3
      Now that I think about it,I might have a set of 45's in my parts box. If not I'll just buy a set at my favorite independent bike shop. Oh GOODIE!!! I get to pull the carbs again.
      1979XS1100SF
      K&N's and drilled airbox
      Jardine 4in1
      Dunlop Elite 3's
      JBM slide diaphragms
      142.5 main jets
      45 pilot jets
      T.C.'s fusebox & SOFA
      750/850 FD mod.
      XV 920 Needle Mod.
      Mike's XS plastic floats set at 26mm
      Venture Cam Chain Tensioner

      Comment


      • #4
        mixture

        You might be able to open those pilot screws a bit more, that usually helps with a hesitation problem.
        2H7 (79) owned since '89
        3H3 owned since '06

        "If it ain't broke, modify it"

        Comment


        • #5
          That would probably the cheapest fix if correct, but it's a pain in the A$$ to get in to adjust them with my big hands. I think I saw a right angle screwdriver to make adjustment easier somewhere on this site, but can't remember where. Must be my rapidly developing CRS.
          1979XS1100SF
          K&N's and drilled airbox
          Jardine 4in1
          Dunlop Elite 3's
          JBM slide diaphragms
          142.5 main jets
          45 pilot jets
          T.C.'s fusebox & SOFA
          750/850 FD mod.
          XV 920 Needle Mod.
          Mike's XS plastic floats set at 26mm
          Venture Cam Chain Tensioner

          Comment


          • #6
            tool

            I have one of those tools, they're great. There is a pic. of one in this thread.....

            http://www.xs11.com/forum/showthread...5&pagenumber=2
            2H7 (79) owned since '89
            3H3 owned since '06

            "If it ain't broke, modify it"

            Comment


            • #7
              Re: Fast Idle or Hard Starting

              Originally posted by Toolmaker Tim
              If I lower the idle to a reasonable RPM I cannot get the bike started easily. If I run the idle at 1500, it starts easily with minimal choke
              The orifices in the bottom of your float bowls are plugged. Look to the second page of this thread for some pictues and a bit of an explanation of what may be your problem.
              Ken Talbot

              Comment


              • #8
                Did not even know they exsisted Ken. I guess it was a good day, I learned something. Carb bowl spooge holes. Has a nice rhythm to it. I remember seeing the hole in the carb bowl gasket and wondering what they were for, but never followed up on it. Bikerphil, thanks for the heads up on the screwdriver thread!
                1979XS1100SF
                K&N's and drilled airbox
                Jardine 4in1
                Dunlop Elite 3's
                JBM slide diaphragms
                142.5 main jets
                45 pilot jets
                T.C.'s fusebox & SOFA
                750/850 FD mod.
                XV 920 Needle Mod.
                Mike's XS plastic floats set at 26mm
                Venture Cam Chain Tensioner

                Comment

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