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    #16
    Originally posted by trippivot View Post
    29 and 33 smoothbores appear identical who measured the inner venturi diameter?

    better start at 127.5 mains and the needle in the middle which may still be too much fuel.

    depending on your engine pilot jet choice is going to be biggest tuning factor.

    12.5 or 15 or 17.5 pilot sizes. maybe a 20 if you have massive low lift flow from a port job and bigger intake valves

    no dyno jet kit !!!! these are very easy to tune -- for half throttle and higher. street use is going to require patience.
    Agreed, VMs are cake to tune, I wish they were all so easy! And yes, they will require a bit of patience and a learned throttle hand...

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      #17
      Originally posted by trippivot View Post
      29 and 33 smoothbores appear identical who measured the inner venturi diameter?
      I don't think so. Stock vm26mm carbs and 29mm smoothbores resemble each other, but 33mm smoothbores look totally different. 33's have gradual tapered inlet throats, 2 screw flat tops (versus 3 screw cupped tops for 29's), totally different racks that they mount to. Dar

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        #18
        Well I just installed the 120 main jets and let me tell you what a difference that made. Needless to say the clutch is not able to hold all the power at the high rpms.

        On the downside it appears the Dynojet needles at 3 1/2 are not going to work. I haven't pulled the plugs yet but it seemed to be rich in the mid throttle. I'm planning on re-installing the stock needles at position 3 and see how that works.

        Also I confirmed my pilot jets are #25. My first impression is it's slightly rich but I have yet to confirm with a plug read.

        Thanks for everyones feedback. This thread has been a real life saver.

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          #19
          Originally posted by Easy Rider View Post
          Well I just installed the 120 main jets and let me tell you what a difference that made. Needless to say the clutch is not able to hold all the power at the high rpms.

          On the downside it appears the Dynojet needles at 3 1/2 are not going to work. I haven't pulled the plugs yet but it seemed to be rich in the mid throttle. I'm planning on re-installing the stock needles at position 3 and see how that works.

          Also I confirmed my pilot jets are #25. My first impression is it's slightly rich but I have yet to confirm with a plug read.

          Thanks for everyone's feedback. This thread has been a real life saver.
          yes put the stock needles back in and set them to P3 and see how that goes if you have a really free flowing pipe then you might need to go to P4 as i did but try P3 first
          if you feel that the pilots are too rich with 25's in then go down to 22.5's check it out and see you should do some plug chops and aee what they tell you
          remember that rich or lean will not be determined by RPM or speed
          but by the throttle position and the throttle position will tell you what circuit to adjust
          idle to 1/4= pilot jet and air screws
          1/4 to 3/4 = needle jet & jet needle
          3/4 to WOT = main jet

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            #20
            Originally posted by Easy Rider View Post
            Well I just installed the 120 main jets and let me tell you what a difference that made. Needless to say the clutch is not able to hold all the power at the high rpms.

            On the downside it appears the Dynojet needles at 3 1/2 are not going to work. I haven't pulled the plugs yet but it seemed to be rich in the mid throttle. I'm planning on re-installing the stock needles at position 3 and see how that works.

            Also I confirmed my pilot jets are #25. My first impression is it's slightly rich but I have yet to confirm with a plug read.

            Thanks for everyones feedback. This thread has been a real life saver.
            I have the same carbs with a Kerker pipe and K&N pods. A 122.5 main and a 22.5 pilot have mine dialed in pretty well.

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              #21
              I installed the #20 pilot jets and set the stock needle back to position 3. It's really close now and may need to move the main or pilot jets one size up or down to get it right on. Detailed plug reads yet to come.

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