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Thread: Carb main jet hole sizes.

  1. #1
    Join Date
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    Default Carb main jet hole sizes.

    Hi guys. Does anyone have the hole diameters for main jets on mikuni vm22 carbs?
    I dont mean the jet numbers but the actual size of the hole for various jet sizes.
    As in
    #80 jet. diameter???

    Up to about #120

    Cheers

  2. #2
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    Somewhere on the net there is an equivalency chart. Google Mikuni jet sizes.
    Because they started as Amal licencees the jet sizes aren't direct measurements.
    Dellorto is better - numbers are mm sizes.

  3. #3
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    If you are planning on drilling the jets, please don't.

    While it may fit YOUR immediate needs, pity the next guy who wants to adjust the jetting, but will be basing it on the numbers he sees.

    .

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  4. #4
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    Quote Originally Posted by Steve View Post
    If you are planning on drilling the jets, please don't.

    While it may fit YOUR immediate needs, pity the next guy who wants to adjust the jetting, but will be basing it on the numbers he sees.

    .
    Ten seconds on the bench grinder and there's no numbers on the jets. That's a pretty good hint they've been drilled.

  5. #5
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    Quote Originally Posted by Steve View Post
    If you are planning on drilling the jets, please don't.

    While it may fit YOUR immediate needs, pity the next guy who wants to adjust the jetting, but will be basing it on the numbers he sees.

    .
    I intend to make my own jets, there are no sizes on the jets in the carbs now so i have no idea what they are anyway and machining my own is a simple no wait solution to rejetting the carbs

  6. #6
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    Have a look at this site.....note their warnings. A set of pin gauges can tell you what size you got now

    https://www.jetsrus.com/a_jets_by_ca..._VM_series.htm
    1981 gs650L

    "We are all born ignorant, but you have to work hard to stay stupid" Ben Franklin

  7. #7
    Join Date
    Jul 2019
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    Denver
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    FWIW
    Buy a good pin gauge set and pin all your jets.
    Mass produced jets are generally off from their stamping.
    I've had jets stamped 120 that have pinned anywhere from 112-128.
    Same goes for emulsion tubes ect..
    2016 Ducati 1299s
    1989 BMW K100RS
    1982 GS1100E-current build
    1980 GS1000E-sold
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