HuaSheng 4 stroke fuel lines

Discussion in 'Frame Mounted Engines' started by chuck216, Mar 1, 2008.

  1. chuck216

    chuck216 Member

    Hi all,

    Here's my first problem while building My bike. The kit I bought comes with the HuaSheng 49cc 4 stroke, which has 3 "nipples" for lack of a better term for feul lines, upon a search of this site I do know the upper bent one is the fuel intake, the lower one on the same side, right side of motor is a fuel vent/return and the one on the carb bowl is an overflow of some kind. What I would like to know is does anyone know the proper way to run each to minimize loss of fuel through it simply overflowing.. like routing it back through a 3 way fuel filter etc. What is the best way? I'm worried about dripping fuel out on the ground.


  2. gone_fishin

    gone_fishin Guest

    my "similar" engine

    i haven't torn into the carburetor yet...the first time i see more than the occasional drop, i'm goin' in...

    i'm not sure of the it dripping now? or are you simply expressing concerns over saving even the tiniest bit of fuel? 2 solutions to that, imo.

    1-switch to a diaphragm carburetor, which uses an active & sealed bypass/overflow as part of the vacuum process. ideally, it's a zero-loss system.

    2-attach a small "catch" can & run both vents/overflow lines into it...don't seal it as there's no pressure behind any normally dripping fuel (if any)...i think if you do this you'll see over time that's there not much lost fuel to be worrying about.

    was this any help?

    corrections or more info?
  3. chuck216

    chuck216 Member

    It's dripping and quite a bit every time I have the petcock open. even while the motor is running
  4. gone_fishin

    gone_fishin Guest

    which line?
  5. chuck216

    chuck216 Member

    The one on the bowl, and also the bowl itself seems to be dripping.. but that can't be right
  6. eltatertoto

    eltatertoto Guest

    check the seals.
  7. gone_fishin

    gone_fishin Guest

    let's start here

    ps-good subject-line, it has the detail needed for future searchability
  8. chuck216

    chuck216 Member

    Thanks augidog.. that lower nut on the bowl seems to be the problem.. it was about 1/2 a turn loose.
  9. Andrew735

    Andrew735 Member

    Im working on my first build with this same type of engine and i wasnt sure on this so correct me if im wrong, but the two clear tubes (like in augi's picture) dont actually connect to anything besides the knobs that they are already attached to and the stright knob under the bend knob is where you attach the fuel line from the gas tank?
  10. Abeagle

    Abeagle Guest

  11. Andrew735

    Andrew735 Member

    Thanks again Beagle! thats what i thought. Now all thats left is to put gas in it, oil the gear box, and see if it runs!
  12. salfter

    salfter New Member

    Actually, the upper tube (bent down and forward) is a vent, the straight tube near it is the fuel inlet, and the one on the bowl is a drain. If you connect the line from the tank to the uppermost tube, I'd expect it to start dripping fuel out of the other tube.

    I posted photos of the carb on my bike as I disassembled it for cleaning a few months ago. In the second-to-last photo, notice that the straight tube on the carb body is routed to the needle valve.