Carb problems... please help!

Discussion in 'Engine, Fuel and Exhaust' started by dafintn, Apr 13, 2009.

  1. dafintn

    dafintn New Member

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    I have a 1981 XLH with stock carburetor. The fuel just keeps pouring out the overflow. I took the carb apart and cleaned it. It was pretty nasty inside the bowl but everything looked ok. So... what might be my problem? Should I buy a rebuild kit or a new carb? What is up with the universal carbs I see on some of the parts aftermarket sites?
     
  2. Dan89FLSTC

    Dan89FLSTC Banned

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    You may have crud under the needle and seat, causing the carb to overflow, also the float level could be set wrong, or a hole in the float causing it to sink...
     
  3. dafintn

    dafintn New Member

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    Float looks good. Which screw will adjust float level. Can you direct me? Or do you know of website that will steer me to that adjustment? Thanks!
     
  4. TQuentin1

    TQuentin1 Well-Known Member Staff Member Moderator

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    Is the stock carb on that bike the Keihin CV40? And do you have a shut-off valve on the tank?

    Does the fuel run out of the carb when operating, or just when you park it?

    TQ
     
  5. dafintn

    dafintn New Member

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    I do have a shut off on the tank and the fuel flows when the engine is off. It comes out the overflow tube. I suspect it is the carb you mention. It is marked JAPAN and HARLEY DAVIDSON.
     
  6. fin_676

    fin_676 Experienced Member Staff Member Moderator Contributor

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    If it is stock wont be a cv didnt fit thoes to sportster till about 88
    but if its the float bowl overflow that the fuel comes out of you may need a new float needle they have a rubber coating on the cone shaped part to help seal when float is up after a time the rubber hardens and fails to give a good seal
    But first you need to know what carb is fitted perhaps investment in a service manual would be a good first step as you will need it from time to time

    Brian
     
  7. TQuentin1

    TQuentin1 Well-Known Member Staff Member Moderator

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    Just read the post from the member above. I did not know that about when the Keihins were put on the Sportys. So this info does not apply. Sorry.

    Well here is some pretty good info on the Keihin CVK40. The "K" stands for Kawasaki, but most of the info here is appropriate for our carbs too. Almost at the bottom of the document, you will find info about the float level. They also describe how to check the level, but if yours is flooding out, you know it is too high. I suspect the member above has it right. Your needle or the seat has some crud that is keeping the needle open. Two choices, clean it, or use your tank valve when parked (should do this anyway!!). I think you should clean it, but inspect the needle and seat carefully for any damage. Don't adjust until you are sure you have cleaned the needle and seat and it is working. As they say in the article, VERY small adjustments are required, and NO, there is no screw - you just bend that little tang!!

    Care & Feeding Of The Keihin Carb

    TQ
     
  8. Caper

    Caper Active Member

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    Smell your engine oil for a gas smell if there is ...change the oil. Stock carb in 81 is Keihin(not CV type) When you park the bike turn off the gas at the fuel shut off at the tank. They will allow fuel past the float valve whether clean seated right or what have you, and could get into the intake, wash down cylinder walls and contaminate the engine oil with fuel, all the fuel might not get out the overflow tube. with an old bike you have to develop old habits....shut down bike,turn off fuel.
    when those carbs work right they're fine..but when they don't ditch em....that's why you see so many shovels with S&S carbs on em. I see a lot of the non CV Keihin's in garages as paperweights. When you feel the need for a new carb pick up a Keihin CV..theyre set it and forget it and work very well.
     
    Last edited: Apr 13, 2009
  9. glider

    glider Veteran Member

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    There's really only two things that will allow fuel to flow out the overflow when parked. A defective float or a bad needle and seat in the carb or even debris keeping the needle open. Clean out the tank and start from there to clean out the fuel delivery regardless of what carb you have.

    All it takes is a small piece of scale or sediment to cause the problem you are having.
     
  10. 3wVo

    3wVo Banned

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    And a float level that is off are your #3 basic needle leaks. You could set the float at a horizontal position, open the fuel so it flows, watch the flow stop or move to the floor or work outside or smoke the house up with gas.

    Waring banner aside, you now push the float up to stop the leak. If it did not stop, it is like glider said. If the leak stops, it is what I said is the 3rd variable.