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Help ZZR carb, what have I done wrong?

Discussion in 'Kawasaki 250cc Twins' started by Martin Green, Jun 8, 2022.

  1. Martin Green

    Martin Green Active Member

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    Hey all

    Just put the carbs from my zzr250 through the ultrasonic cleaner and put them back together.

    When I let fuel through the line the fuel pours out of the two holes at the opening of the Venturi. The ones facing the air-box at the very bottom. Have I got the float height wrong?
    I didn't actually touch the tangs as it wasn't leaking before so I must have got something else wrong. If it was the floats would it not pour out of the overflow rather than those two holes?

    Its actually squirting out!

    Thanks
     
  2. jmw76

    jmw76 Well-Known Member

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    Have you connected the fuel line up to the correct spot? Are you sure you have not connected to one of the breather hoses?
     
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  3. Linkin

    Linkin The Mechanic Premium Member Contributing Member Dirty Wheel Club

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    I have found that float needles often do not seat properly. Take the bowls off, give the floats a little push and check movement of the needle. Sometimes they get stuck and if pushed gently, will give a little 'click' and seal properly after that.
     
  4. Martin Green

    Martin Green Active Member

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    Thanks for the messages

    yes, fuel line is connected correctly.

    If the bowls are over filling would the fuel come out if these 2 holes?

    im using a remote tank and have blocked the vacuum pipe that goes to the petcock normally.
    The fuel is literally squirting out of the holes.
    I thought it would come out of the overflow rather than here?
     
  5. Murdo

    Murdo The Good Doctor Staff Member Contributing Member Ride and Events Crew

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    Have you got the floats in upside down? Very easy to do on some carbs.
     
  6. Martin Green

    Martin Green Active Member

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    I did look at that actually Murdo, but not possible in this instance.
    If fuel can come from these holes if the float bowl is over filling then I must need to check the heights again.
    Would being on the centre stand change the angle enough to overvfill?
     
  7. Murdo

    Murdo The Good Doctor Staff Member Contributing Member Ride and Events Crew

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    No.
     
  8. Martin Green

    Martin Green Active Member

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    This is really weird,
    It’s still doing it.
    I’ve even connected the carbs to my remote fuel tank with the float bowls removed and carbs suspended,
    I let the fuel flow though and when I push the floats up it stops the flow.
    When I put it all back together I still get fuel pissing out of those two holes.
    WTF!

    it’s almost as though the fuel is getting there regardless of how full the Bowls are.
     
  9. jmw76

    jmw76 Well-Known Member

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    Can you post some pics of the installation and maybe one showing the fuel flowing out.
    Does it flow out of all carbs or just one?
     
  10. Martin Green

    Martin Green Active Member

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    Yeah I’ll put a YouTube link up.
    Both carbs are doing it.
     
  11. Martin Green

    Martin Green Active Member

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  12. Murdo

    Murdo The Good Doctor Staff Member Contributing Member Ride and Events Crew

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    Got to be the float valves not shutting off. Does the needle seat have an O ring around it and is it a tight fit into the carb body?
     
  13. jmw76

    jmw76 Well-Known Member

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    Wow. They really are leaking. You must have put something back incorrectly. Those float bowls are just over flowing really badly.
    Maybe take the float bowls off. Invert the carbs and post another pic.
    Very strange.
    Are the needle valves new? Are they the correct ones?
     
  14. GreyImport

    GreyImport Administrator Staff Member The Chief Contributing Member

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    Last edited: Jun 11, 2022
  15. Martin Green

    Martin Green Active Member

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    Once again thanks for all of your help.

    If I suspend the carbs without the bowls attached and let fuel through, I can shut off the fuel flow by manually lifting the floats.
    As soon as I refit the bowls and rely on the floats buoyancy to stem the fuel flow they fail
    Its as if the floats buoyancy is not strong enough to shut the valve.
    I’ve looked through the exploded diagrams and all is correct.
    The float needles are not new but have been through the ultrasonic cleaned and their tips look unworn under the magnifying glass.

    I can’t find anything on the diagrams but is there suppose to be a filter or something in the brass outlet that the float needles drop into ?
     
  16. GreyImport

    GreyImport Administrator Staff Member The Chief Contributing Member

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  17. Murdo

    Murdo The Good Doctor Staff Member Contributing Member Ride and Events Crew

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    A/ Make sure your floats actually float. Take them out and put into a dish of petrol to see what they do (punctured floats are fairly common, they fill with petrol and become sinks).
    B/ Check that the floats move with the bowls on as sometimes the floats get bent and will jam/stick to side of bowl and not shut off needles. Give carbs a shake and listen for the floats moving.
     
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  18. jack_lee

    jack_lee Active Member

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    is there any updates?
     

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