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Carburetor jet

Discussion in 'The Garage' started by Bikebone, May 16, 2020.

  1. Bikebone

    Bikebone XS400 Member

    I'm currently cleaning and replacing worn out parts in my 1982 Yamaha 400 SJ carburetor. I recently noticed two of the same jets were different.....one had multiple holes and the other had none (see attached photo). I'm not sure if it makes a difference when I come to placing the jet in either of the carbs.

    Attached Files:

  2. NewHavenMike

    NewHavenMike 1976 XS360C Top Contributor

    Both jets are used in the XS bikes. The one with the bleed holes is for XS360 carbs only. DONT throw it away. They are somewhat hard to find. What size is it? 17.5?

    Correction- The 17.5 is the non-bleed type and thats what goes in 360s carb only. Sorry, my memory tricks me sometimes.... OK most of the time.
    Last edited: May 16, 2020
  3. xschris

    xschris XS400 Guru Top Contributor

    Yours should have the bleed type pilot jet. If you buy new ones get real mikuni jets they are far better the any others. jetsrus.com has them.
  4. Bikebone

    Bikebone XS400 Member

    Thank you for the reply.

    Question: Only one has the bleed hole, does it matter what side of the dual carb it goes back into??
  5. Gra900

    Gra900 XS400 Addict

    I really wouldn’t recommend using the one without bleed holes at all. The way these things work is that air is sucked in through the pilot air jet, and through a drilling gets to the air holes in the pilot fuel jet. There it mixes with the fuel and a vaporised fuel air mix goes through more drilling’s to the Pilot Jet and then out into the carb float through the little hole just after the butterfly. You control idle by screwing the Pilot Jet in and out.

    Attached Files:

  6. Bikebone

    Bikebone XS400 Member

    I can't determine if the last owner messed with carb. and replaced one of the jets with one that has bleed holes (or does not have bleed holes)?? Or has it never been messed with and it came from the factory with the duel carb. having one of the two jets with bleeder holes?? One would think they should be the same......right??
  7. xschris

    xschris XS400 Guru Top Contributor

    You need both bleed type jets.
  8. Bikebone

    Bikebone XS400 Member

    Thank you. Placed my order with Jetsrus.com
    xschris likes this.

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