Info Yamaha FZR250R 3LN custom carby mod's

Discussion in 'Yamaha 250cc In-Line 4's' started by my67xr, Jun 22, 2019.

  1. my67xr

    my67xr Bike Enthusiast Staff Member Premium Member Contributing Member

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    On the FZR250R 3LN carby's the mixture screw's sit underneath the fuel bowl, are are recessed about 35mm.
    I have been thinking about modifying some mixture screws on my FZR to make it a bit easier to tune.
    Thought if i drill and tap the slotted end and use some standoff spacer's with some thumbscrews on the end i can make the mixture screw's easier to access and tune
    You can buy extended mixture screw's for different model carburetor's, but i'm not sure if any of them will fit the BDST28, and some of them are a bit expensive too
    These long mixture screw's suit the Suzuki GSF250 and are $89 US, plus $48 post for a set of 4x including spring's, washer's and o'ring's, so all up $197 AU !!

    Extended_Fuel_Screw,5020M,SUZ,13279-47070.jpg



    I went on ebay and had a search, i ended up buying these brass 35mm long M3 M / F threaded standoff spacer's x10 off ebay for $6 inc post
    https://www.ebay.com.au/itm/252335623455

    And these M3 x 7mm thumbscrews x10 for $6 inc post
    https://www.ebay.com.au/itm/273827119747


    s-l1600.jpg s-l1600.jpg

    20190622_094527.jpg

    20190622_094613.jpg

    They should end up looking like this when finished and fitted, i will mark the end of the knob with a line on one half so i can accurately set them by hand
    And i will loctite the thread's so they can't fall apart from vibration's


    20190622_095024.jpg




    Now to drill and tap some mixture screw's





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    Last edited: Jun 22, 2019
  2. risky

    risky risky

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    clever solution.
     

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