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    Jet size quick question

    I was going through some older post and found this chart;

    0.0500---- 130--------- 122--------- 114.4
    0.0510---- 132.5------- 124--------- 116.3
    0.0520---- 135--------- 126--------- 118.1
    0.0530---- 137.5------- 128--------- 120

    Now it seems when doing PODS the 3 up on main and 1 on pilot seems to be a good starting point. After some more research the Mikuni BS lists the main at 115 from the factory. If I read this right I order by the orifice size on the left????? I am using the UNI's with the covers that are oiled. I guess that puts me at a 120; the right hand list is for Mikuni. Any objections before I order or recommendations? Exhaust is stock and no leaks. Again this is where I am starting probably not staying. Also I want to use a brass fitting and a clear tube to check my floats, any suggestions and size help on the brass fitting? I also thought about setting it a touch high to help with an off idle hesitation. I have been messing with the air bleeds but am not totally satisfied. 21/2 turns out seems the best.

    #2
    Originally posted by jeffgs View Post
    I was going through some older post and found this chart;

    0.0500---- 130--------- 122--------- 114.4
    0.0510---- 132.5------- 124--------- 116.3
    0.0520---- 135--------- 126--------- 118.1
    0.0530---- 137.5------- 128--------- 120
    Nice chart, but without any context, it's rather meaningless.
    What are the numbers in the left column?
    The second column might be Mikuni main jet numbers.
    The third column might be Dynojet main jet numbers
    I have no clue what the fourth column might be.


    Originally posted by jeffgs View Post
    Now it seems when doing PODS the 3 up on main and 1 on pilot seems to be a good starting point.
    If you have some rather restrictive pods, that might be true. I have always seen the rule of thumb that says "4-6 sizes up on the mains for pods". I have no idea why you would need to go up on the pilots. The pods do allow more air to flow than a stock airbox, but that only shows up at high flow rates. Idle and low-throttle speeds are not exactly "high flow". The throttle is doing the restriction there, not the airbox, there shouldn't be any changes necessary, other than richening up the mixture screw a bit.


    Originally posted by jeffgs View Post
    After some more research the Mikuni BS lists the main at 115 from the factory. If I read this right I order by the orifice size on the left?????
    Yes, the stock jets are 115. What difference does it really make what the actual orifice size is? You say you are reading a 3 size increase, that would put you at 122.5, not 120. If it were my bike, I would start with 125s and be ready to move a size or two in either direction.


    Originally posted by jeffgs View Post
    Exhaust is stock and no leaks. Again this is where I am starting probably not staying.
    When you get done with all the "fun" of tuning for your pods, you might want to re-think going through all that again when you change your exhaust.


    Originally posted by jeffgs View Post
    I also thought about setting it a touch high to help with an off idle hesitation.
    Do yourself and your bike a favor, ... set them within the proper range. At the top of the range, if you want, but in the range. Also keep in mind that "setting them high" will mean that you use a smaller number to set your float height. If you raise your float level to 'cure' an off-idle problem, you will also richen up the midrange and the top end, so you will have to re-tune them, too. To help with your off-idle hesitation, richen the mixture (pilot) screws a bit.


    Originally posted by jeffgs View Post
    I have been messing with the air bleeds but am not totally satisfied. 21/2 turns out seems the best.
    Your carbs do not have "air bleeds". The only external adjustment you have is what Mikuni calls the "pilot screw", many of us also use the term "mixture screw". We call it that because it controls the amount of a pre-set mixture, not just air. Turning it out will richen the overall mixture, turning the screw in will lean it out. I generally start at 3 turns out, then fine-tune for best idle and overall throttle response. If you turn them to 2 3/4 turns, you might get rid of most of your off-idle problem.

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      #3
      Nice chart, but without any context, it's rather meaningless.

      Read my post again, maybe the wrong word but orifice is on left, Mikuni is on right. As far as air bleeds; again wrong word. I have a high stress job and pounded out the post. I apologize.

      I do appreciate the imput and will start with 125. I have listened to after market exhaust and do not like the way they sound. If i could cobble one together that sounded like a thumper then maybe. I am entertaining this to open up the bike and move the battery.

      As i have understood in the past raising the float hight will trigger the signal a touch sooner (can't remember the term), i may have not properly understood that to mean it would richen it through the range, i thought that would be more determinate on needle size and the speed of the taper.
      Last edited by Guest; 03-02-2015, 09:19 PM.

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        #4
        This one is much more complete and easier to read.

        MY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
        1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550

        NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.


        I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.

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          #5
          Chuck

          Thank you. That is the one i copied and pasted from one of your previous post.

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