Help Needed With My Carbs Please

Discussion in 'Technical Help' started by KevofCov, Aug 15, 2023.

  1. Eldon

    Eldon Elite Member

    Nov 14, 2018
    6,188
    800
    North Yorkshire
    ZZR 600 had a set of shims available to go under the needle retaining clip to give a similar effect.
    The shims were a given thickness so as to enrichen the fuel flow and negate the effects of aftermarket pipes weakening the mixture and avoiding creating a stumble on acceleration.
     
    • Agree Agree x 1
  2. t552

    t552 Senior Member

    Nov 17, 2014
    416
    113
    Bristol UK
    Amost certainly pilot jets. You need to poke them through with copper wire. Air, ultrasonic cleaned just dont work.
     
  3. Wire-Wheels

    Wire-Wheels Elite Member

    Apr 26, 2019
    2,497
    800
    California - USA
    The Mikuni BST36's have several grooves at the top of the needle to make the adjustment. It is the last tuning point on these carbs, The pilots are to set the idle mixture. The main jets are to set the upper range. Setting the needle height tunes out the flat spot in between. If you change either the mains or the pilots, this may need attention. I like Mikuni's because, they made provision for this by providing an adjustment there. ...J.D.
     
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  4. KevofCov

    KevofCov New Member

    Mar 20, 2019
    9
    3
    End of M69
    Thank you for the interest gents.


    J D I’ve ruled out the ignition – starts and behaves normally using the choke


    Eldon Proper tank is on a shelf. Feeding fuel directly into the carbs from a small plastic mower tank


    J D Was running great when put away 2 years ago. A sticking float valve in July means that all I’ve done is change all 4 float valves
     
  5. Eldon

    Eldon Elite Member

    Nov 14, 2018
    6,188
    800
    North Yorkshire
    But is the correct fuel tap a vacuum operated one i.e. not constant gravity fed?

    By the sound of it your fuel supply is now constant which the system may not be able to accept.
     
  6. KevofCov

    KevofCov New Member

    Mar 20, 2019
    9
    3
    End of M69
    Just realised that I have not checked the pilot jets......
     
  7. KevofCov

    KevofCov New Member

    Mar 20, 2019
    9
    3
    End of M69
    t552 - your a star. I think you have found the issue. Not had a lot of time today but have removed one and it was blocked :cool:
    Will be back out there tomorrow....
     
    • Like Like x 1
  8. Kev of Cov

    Kev of Cov New Member

    Jul 28, 2017
    2
    3
    West of Leicester
    Great news gents. She is purring like a Tiger again. All is normal. Thank you all for taking the time to add your thoughts.

    Big mention to T552 who was spot on. Pilot jets blocked. Drain those float bowls gentlemen.


    Everyday a sckool day….
     
    • Like Like x 1
  9. Wattie

    Wattie Well-Known Member

    Feb 25, 2020
    352
    63
    UK
    Good to hear the bike is running fine but could you do me a favour and tell me why you ignored my advice about the pilot jets in post number 12 of this thread? I'm interested to know how to word any advice in the future?
     
  10. Kev of Cov

    Kev of Cov New Member

    Jul 28, 2017
    2
    3
    West of Leicester
    Hi Whattie

    Absolutely nothing wrong with your advice or the way you present it. What you failed to allow for is muppets like me that didn’t know that I had pilot jets. I typed my post no. 13 before looking at your suggested Kev’s shed vid. At 15min55ses I discovered that I have pilot jets.
    Its clear that I was mistaking my emulsion tubes for pilot jet.

    I got there in the end 'spose

    Many thanks again for taking the time to add to the thread.
     
  11. Kev of Cov

    Kev of Cov New Member

    Jul 28, 2017
    2
    3
    West of Leicester
    I’ve been sat on the sofa tonight in me pants watching youtube. Learnt a lot from this vid






    Especially 5min 57secs
     
  12. Wattie

    Wattie Well-Known Member

    Feb 25, 2020
    352
    63
    UK
    Ah, thanks for explaining. Glad you got there in the end and fixed it yourself, it's very rewarding. Also nice to hear another trophy 12 owner keeping it on the road.
     
  13. KevofCov

    KevofCov New Member

    Mar 20, 2019
    9
    3
    End of M69
    #33 KevofCov, Nov 5, 2023
    Last edited: Nov 10, 2023
    Just for info – I was keen to synchronise the carbs. The master is no 3 and has no adjustment (no. 1 is the first carb on the n/s). Set the rest to this.
     
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