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  1. #1
    TX21's Avatar
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    Mikuni 40 type 2

    On the carbs with no fuel pump (since they have a accel. pump) there are no check valve/diaphrams for the inlet and outlet. So I guess fuel can flow either way? What stops the fuel from going either way or I guess it dosen't matter since the other carb has the valve and I guess it does the job for the carb without?


  2. #2
    TX21's Avatar
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    Got my answer, the check valve is in the accelorator pump. Just gota test them pump now!

  3. #3
    TX21's Avatar
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    Alright still have some questions. Here are the carbs, they are from a 97 xp with a 787 motor. The carb with no acc. pump has no check valves so how do I check the carb other than the pop off? Both carbs pop at 38 psi so thats good. The one without the acc pump (the MAG side) has check valves but they don't stop any pressure. How is this possible? I hook up the tube and apply pressure and the air goes both ways? I have changed the valves and gaskets but no help! And the carb with the acc. pump (PTO) has no valves I heard the pump takes care of this so how do I check that?
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  4. #4
    Which Check Valves are you talking about ?

    That Green in-line fitting coming from the Accel. Pump Tubing has a tiny metering Jett in it---it's not
    a Check Valve and will allow pressure both ways.

    Any other "Check" Valves internal to the Carbs. (on the metering Block) cannot
    be tested--but seldom fail if they are installed correctly.

    The "Check" Valves of the MAG. Carb. in the Fuel Pump will work fine
    if the Clear Plastic diaphragms are installed with a side UP which
    has the blue mark on it from the rebuild kit.

    A Pop-Off test and pressure test 3~4psi below Pop-Off which holds
    pressure are the only other tests you can do to verify Carb. rebuilds
    other than install them and dial them in---


    DvD

  5. #5
    TX21's Avatar
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    Quote Originally Posted by David_HX_RXP View Post



    The "Check" Valves of the MAG. Carb. in the Fuel Pump will work fine
    if the Clear Plastic diaphragms are installed with a side UP which
    has the blue mark on it from the rebuild kit.

    A Pop-Off test and pressure test 3~4psi below Pop-Off which holds
    pressure are the only other tests you can do to verify Carb. rebuilds
    other than install them and dial them in---
    I installed them right with the marked side up. In the procedures written to test the carbs it says to put a clear tube on the in line and make ture there is notthing coming out and do the same for the out line and nothing should go in.

  6. #6
    Quote Originally Posted by TX21 View Post
    I installed them right with the marked side up. In the procedures written to test the carbs it says to put a clear tube on the in line and make ture there is notthing coming out and do the same for the out line and nothing should go in.
    Never heard of that test proceedure. What book is it from ?

  7. #7
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    Quote Originally Posted by David_HX_RXP View Post
    Never heard of that test proceedure. What book is it from ?
    From this link

    http://www.seadoosource.com/mikunitests.html

  8. #8
    TX21's Avatar
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    Anyone? This can't be that complicated what am I missing?

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