Q's about rejetting oem carbs......

Discussion in 'WERA Vintage' started by SpeedyE, May 21, 2020.

  1. SpeedyE

    SpeedyE Experimental prototype, never meant for production

    I am going to be cleaning an old set of oem 1986 carbs very soon. I am also adding a Yosh 1980's 'Race-only' duplex pipe to the bike, that a WERA friend got for me.

    I can disassemble the carbs (I have disassembled carbs before back in the 1980's), and was planning on using a sonic cleaner filled with Carb cleaner, And then replacing o-rings etc, and then reassemble. Is this the correct method?

    I plan on using the stock airbox, with a new NOS filter.
    I plan on buying the Motion-Pro Carb-synch tool.

    I have no idea how to jet the oem carbs for the addition of the Yosh Duplex, not really for peak power, but more for reliable/correct idling/accellerating/functionalability.

    Can anyone offer me any advices or steer me in the right direction. I am in uncharted water for me.
    Thank you.
     
  2. DonTZ125

    DonTZ125 Purveyor of Neat Toys

    There are 'how-to' articles on jetting 4-stroke CV carbs - I assume this is what you're talking about, given the Yosh pipe. The only thing I will add is to not bother trying to clean your pilot jets; pitch 'em, and replace with new. The bore is so small that any amount of deposits/ fouling / scratching will affect the flow.
     
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  3. SpeedyE

    SpeedyE Experimental prototype, never meant for production

    THank you, Don.
    I just looked....the Hendler carb repair kit does have a brass jet and stainless pointy thing (main/pilot-jet?) with the o rings.
    Thank you for the advice/info.
     
  4. SpeedyE

    SpeedyE Experimental prototype, never meant for production

    I have 4 of these kits, plus a NOS petcock.....

    carb1.JPG
     
  5. SpeedyE

    SpeedyE Experimental prototype, never meant for production

    Thinking back in my memory banks, i think that silver thing has to do w the float-bowl
    ?
     
  6. Kurlon

    Kurlon Well-Known Member

    You'll want to order pilot jets still, that's a needle and seat for the float bowl, not jets.
     
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  7. SpeedyE

    SpeedyE Experimental prototype, never meant for production

    Thank you!
     
  8. SpeedyE

    SpeedyE Experimental prototype, never meant for production

    Would Yoshimura know what #size jets I am supposed to install with that specific pipe & OEM airbox?
     
    Last edited: May 21, 2020
  9. John Branch

    John Branch The REAL92

    Get a Factory Jet Kit
     
    SpeedyE likes this.
  10. SpeedyE

    SpeedyE Experimental prototype, never meant for production

    Thank you guys.
    I just talked to a local friend who reccomended a local guy to dyno/o2-sensor(?) it.
    Imma do the carb cleaning, assemble the bike, then have local dyno-expert jet it.
    Thank you guys!!!!!!!!!
     
  11. VFR#52

    VFR#52 Well-Known Member

    Best advice I can give you is never take the carbs off the rack.
    The air screws and pilots are always stopped up after sitting and buy new needles for floats.
    Loads of tricks to clean them out.
    Sonic clean works and others tricks as well.
    Buy a Factory Pro jet kit and follow instructions.
    Pump gas with ethanol go up 10 sizes on mains and open air bleeds out half a turn to 1 full turn.
    Any questions just pm me.
    Also things change if you use a K&N filter.
    Jet kit has info in it.
    Have fun.

    Steven
     
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  12. dobr24

    dobr24 Well-Known Member

    All great advice except the ethanol gas comment. Never run ethanol gas in carbs. NEVER EVER EVER EVER! Sorry for yelling. Go to a tool rental place and buy non ethanol. Better yet use this website to find non-ethanol.
    https://www.pure-gas.org/
     
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  13. SpeedyE

    SpeedyE Experimental prototype, never meant for production

    ""Factory Pro jet kit ""

    :clap::flag::clap:

    Thank you guys!!!!!!
     
  14. John Branch

    John Branch The REAL92

    I highly suggest you NOT listen to vffrr52! Go up 10 jet sizes on the main?
     
  15. VFR#52

    VFR#52 Well-Known Member

    Bahhhahahhaha
    So you still butthurt john?
    I'm sure you will get over it one day.
    Now just to clarify that's only if you use ethanol pump gas.
    Because the jet kits where made way before ethanol was in fuel just so you know.
    So all the research was done then.
    But by all means John share when the last time you jetted a carb on a 4 cylinder race bike?
    Guy asked a question and you want to use it to cry about me.
    Man up dude and either help like you did when you suggested factory pro jet kit.
    But dont start your crying session on this guys post about whatever problem you have with me.
    Make a new post if you have to continue this about me.
    More important things in life.

    Steven
     
  16. John Branch

    John Branch The REAL92

    Your a dipshit . Steve :whoosh:
     
  17. John Branch

    John Branch The REAL92

    You might go up that many sizes on the main jet ? If you use something like p.o. In your fuel? Idk for sure? Vffr might can chime in? He knows alllll.
     
  18. John Branch

    John Branch The REAL92

    Hmmm, I just installed a factory jet kit in my vfr400 carburetors not long ago. DIPSHIT:Poke:
     
  19. VFR#52

    VFR#52 Well-Known Member

    Bahhhahahhaha
    I want to apologize for John being butthurt and using this post to call me names.
    He has my phone number for yrs now and he has been offered the chance to come sitdown and say whatever he likes to me.
    When I saw he had replied with info I took a chance that the advice I gave was to be used through my experience with carbs and that John wouldn't bring his feelings on this post.
    For that I'm truly sorry he did that.
    Need anything just PM and be happy to help you any way I can.

    Steven
     
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  20. kenessex

    kenessex unregistered user

    You're
     
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