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Jets for 650

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  • Jets for 650

    Good afternoon all. I'm in the UK and about to fit pod filters to a 1988 Bros 650. My go-to supplier for jets is Allen's Performance. I know what sizes I want to try, but am not sure which are the correct actual jets. To make life difficult, the stock jets are in the carbs and the bike is currently not here. So I wondered if anyone was able to tell me which of the Keihin jets in this identification chart might be the right ones? I *think* the main might be the second one down, but have no idea about the pilot jet. I also need to know whether the I/D of the shims should be 2.7mm or 3.2mm. Can anyone help, please?

  • #2
    You can find the sizes of the jets on this page:

    should be 42 or 45 on the slow jets and probably around 160/165 on the mains. You will have to play with the jet sizes though.

    No idea on the shims. I have a factory pro kit with an adjustable needle.
    Brian - Richland, WA
    1991 Hawk GT


    • #3
      Pilots are N424-21
      Mains are 99101-393
      BE ABSOLUTELY POSITIVE you only get REAL Keihin jets, nothing third party.


      • #4
        Thank you, very much appreciated.

        Does anyone know about the I/D for shims?
        Last edited by geraldthehamster; 08-24-2021, 12:17 PM.


        • #5
          3mm ID, 7mm OD, 0.5mm thickness.
          Hawk with many differently shaped fuel tanks.