Petcock location on inframe fuel tank?

Discussion in 'Motorized Bicycle Welding, Fabrication and Paintin' started by jimthebarron, Nov 21, 2013.

  1. jimthebarron

    jimthebarron New Member

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    Hi, just wondering where to locate the petcock on my Nirve inframe fuel tank. Does it have to go right above the carb or can it go further down the tube behind the air filter closer to the seat tube which would carry more fuel?

    Cheers Jim

    [​IMG]
     
  2. bairdco

    bairdco a guy who makes cool bikes

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    above the carb is best since it's gravity fed.

    with the tank sloping down you won't get all the fuel out. there will be some vacuum with the engine running, but not enough once the fuel passes the petcock to drain the tank.

    if you put it all the way back below and behind the carb, the weight of the fuel may be enough to push it to the carb, but as the fuel gets lower it might starve.

    if the bike is running the vacuum might keep it flowing but starting it when the fuel is low could be a problem.

    ideally you'd want to cut the tank open and block it off at the level point, but that's a lot of metal work.

    if you cut down the motor mounts and get a shorty intake you may be able to lower the engine to squeeze a little more out of it.
     
  3. jimthebarron

    jimthebarron New Member

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    Hi bairdco,

    Many thanks for that, I am going to try and lower the engine so that I can put the petcock above the carb to be on the safe side.

    Cheers Jim
     
  4. curtisfox

    curtisfox Well-Known Member

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    Bairdco is right: but don't realey have to be above the carb all the way just above the float bowel. So the line or gas runs down hill to the input port or hose barb.

    The other thing you can do is get a fuel pump from AKG or other sorce then you can put it any were. .............Curt
     
  5. scotto-

    scotto- Custom 4-Stroke Bike Builder

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    Ditto what Curt said....... petcock opening above float bowl level will work fine.
     
  6. curtisfox

    curtisfox Well-Known Member

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    Looking at the picture the carb is not level and should be, Maybe redo the intake it would also drop the carb some so the pecock could be lower yet.............Curt
     
  7. KCvale

    KCvale Active Member

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    In short you want the petcock at the lowest point of the tank like the GT2 frames have and a venting fuel cap.
     

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