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Big improvement with larger pilot jet on GS 1000 with pods

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    Big improvement with larger pilot jet on GS 1000 with pods

    I've been going around in circles trying to get my BS 32 CV carbs to run with pods on my GS 1000 XP.
    The last issue that was really driving me crazy was a slight stumble coming off idle.
    The idle ran perfectly and from 1/8 throttle to full throttle no problem but when I moved the throttle away from idle very smoothly as when you are driving in traffic the engine would hesitate.
    Following GSR fellows advice, I tried enrichening the mixture with the idle mixture screw but the problem remained
    In the end, I reread the very good article from Koolaid_kid about adjusting the idle on CV carbs and discovered that there is a "bypass outlet" just behind the "pilot outlet" that feeds the engine when coming off idle
    When you look at a cut-away of the carb, you can see that the A/F ratio for the bypass outlet is controlled only by the pilot jet
    In no time, I changed the existing size 40 pilot jets for a set of 47.5 jets I had.
    I closed the idle mixture screw from 2,5 out to 1,5 turns out and BINGO no stumble anymore.
    I only wish I had done this before despite the Dynojet kit's advice that the pilot jet doesn't need to be changed...
    Who gives out the PhD's for CV carb tuning
    sigpicJohn Kat
    My bikes: CB 77, GS 1000 ST Cafe Racer with GSXR 1052 engine, GS 1000 ST, XR 41 Replica with GS 1085 engine,
    GS 1100 SZ Katana with GS 1135 EFF engine, KTM Superduke 1290 R 2020

    #2
    The standard setup for gs1100 16v with pods and 4:1pipe is (along with dj kit) to increase the pilot jets from 45 to 47.5.
    This seems to apply whether using bs34 or bs36.
    With a 4:2:1 pipe I went back to the 45 pilot.
    Glad you have it sorted

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      #3
      Originally posted by posplayr View Post
      The standard setup for gs1100 16v with pods and 4:1pipe is (along with dj kit) to increase the pilot jets from 45 to 47.5.
      This seems to apply whether using bs34 or bs36.
      With a 4:2:1 pipe I went back to the 45 pilot.
      Glad you have it sorted
      I almost bought myself an A/F ratio meter like you did to sort it out
      The issue is always the same: too rich or too lean? When you've never done this in your life it's not easy to diagnose the problem.
      I've tuned a turbocharged car also but with a fully digital control unit, it's way easier to go back and forth with a few key strokes while keeping an eye on the AFR meter
      sigpicJohn Kat
      My bikes: CB 77, GS 1000 ST Cafe Racer with GSXR 1052 engine, GS 1000 ST, XR 41 Replica with GS 1085 engine,
      GS 1100 SZ Katana with GS 1135 EFF engine, KTM Superduke 1290 R 2020

      Comment


        #4
        Originally posted by John Kat View Post
        I almost bought myself an A/F ratio meter like you did to sort it out
        The issue is always the same: too rich or too lean? When you've never done this in your life it's not easy to diagnose the problem.
        I've tuned a turbocharged car also but with a fully digital control unit, it's way easier to go back and forth with a few key strokes while keeping an eye on the AFR meter
        The further you get from the standard setups the more you need the AFR meter. It is still worth it if you want to get peak performance. No need to leave it on the bike, but getting it set up helped mine considerably,

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