How Would You Plug Your Gas Cap?

Discussion in 'General Questions' started by 5-7HEAVEN, May 22, 2009.

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  1. 5-7HEAVEN

    5-7HEAVEN Guest

    As most of you know, the underbelly gas tank on many engines lay 90 degrees off of what they were made to position. Soooo, we MBers can't fill the tank to full capacity.

    In my case, I have two engines, front and rear. Their tanks are filled from a larger reserve tank. Gravity feeds both engines' tanks, and sometimes I assist fillups with a large siphon bulb in the main fuel lines.

    However, gravity fills are unpredictable and gasoline spills out of both gas caps. (To ensure more dependable fillups, I'm installing an aftermarket 12volt electric fuel pump in the main line, but that's another issue.)

    My question do I plug the gas caps so the tanks don't spill? I rarely open the gas caps, only when gravity feeding doesn't work.

    Does anyone have a part # for gas caps on TLE43cc Mitsubishi engines? :icon_cry:

  2. If you seal them gravity feeding really won't work. If I understand you correctly.
  3. Porkchop

    Porkchop Member

    Be more specific. Where are they leaking ? Bewteen the threads on the tank and the cap, or through the vent hole in the top of the cap ? I have a few thoughts ! Are you sure you don't have a vacuum problem ? The upper most cap would definitely need to be vented.

    ..... PC .....
  4. fetor56

    fetor56 Guest

    How about a proper fuel proof 0-ring seal(their big & brown in color) & an extension plastic breather hose on the cap(like certain Trail Bikes)

    PS....did u ever get(or make) that welded bracket for your 460 pull start.....i've got an idea?
    Last edited by a moderator: May 22, 2009
  5. 5-7HEAVEN

    5-7HEAVEN Guest

    Charlie I DID have a vacuum problem on the front engine when it was brand new. It would quit running after a mile, then restart after loosening the cap. After another mile, the problem reappeared.

    This issue was resolved when I installed the reserve tank and fuel supply lines.

    The caps definitely leaks from the vent hole, and maybe from small holes on their undersides along the edges. Gas also leaks at the grommets atop the tank.

    Methinks the proper o-ring that fetor mentioned and a plugged vent hole would solve leakage.

    Firebelly, if necessary, vents can be added topside.
  6. Porkchop

    Porkchop Member

    O.K. Let me see if I can make this simple. You know me ! First of all, if your main feeder/supply tank is higher than the two tanks you're feeding, sure the vents in the top of the lower tanks are going to leak fuel. Gravity, siphon effect ! As long as your main tank has a vent in it, you should be able to plug the vents in the other tanks. Not being sarcastic, but why do you need the siphon bulb ? I'm thinking if you've got a good vent you shouldn't need that, unles these samll engines don't have enough vacuum through the carbs to suck the gas in ! I'm cncerned about that issue myself with the new tank I've got coming ! I'm going to find your video again. I vaguely remember what you bike looks like. Bu I know it has 2 engines ! Hee ! Hee !
  7. fetor56

    fetor56 Guest

    Please answer fetors question or he'll hold his breath indefinately & you'll be very very sorry. :grin5:
  8. 5-7HEAVEN

    5-7HEAVEN Guest

    Ooops sorry fetor. I mentioned your o-ring but forgot about the pullstart question.

    No, I have not fabbed the bracket. BOTH engines have the original pullstart mechanisms so I need two.

    I already bought the Zenoah pullstart and metal pawl, so just need two metal brackets.

    Unsure if I like paying $42 for them. Maybe I'll ask my nephew. He's a welder but he lives on another island.

    I did meet a female welder on my job. She offered to trade services. There was a conflict of interest so I declined.:sweatdrop:

    But I'll remember her offer for the rest of my life.:devilish:
  9. Happy Valley

    Happy Valley Active Member

    Or a source? I lost one yesterday. :dunce:
  10. fetor56

    fetor56 Guest

    I found this steel fence post & figured if one side could be made flat it would serve as a good bracket(without welding)
    Only additional thing would be grinding it to the perfect shape.
    Shame that when it's crushed in a vice it fractures along it's entire edge.
    Plan B(dunno yet) cos i figure i'll eventually be needing this mod myself.


    PS...i'll cut out another piece tomorrow & try getting it red hot first,then shaping it.
    Hope things are going well with your new welder girlfriend. :)
    Last edited by a moderator: May 23, 2009
  11. 5-7HEAVEN

    5-7HEAVEN Guest

  12. 5-7HEAVEN

    5-7HEAVEN Guest

  13. 5-7HEAVEN

    5-7HEAVEN Guest

    Staton has caps:

    Last month my rear engine's tank bracket broke. The next day someone "borrowed" the gas cap from my front engine. I ordered the fuel tank from Staton, which came with cap, lines and filter.

    :idea:So the new cap went on the front engine and the new tank went on the rear engine.
  14. fetor56

    fetor56 Guest

    Thanks for the thought man,i'll go my seperate way....if necessary i'll weld a bracket.
    If your getting that T section in stainless steel it's going to be hard to work.Hard but not will be impossibly strong that's for sure.
  15. 5-7HEAVEN

    5-7HEAVEN Guest



    I installed self-tapping screws into both gas cap's vent holes. This stopped gas from dribbling out.

    Air is being vented from the reserve tank, or leaks from the engines' aging fuel grommets.

    Now I don't smell like gas whenever I ride "The Dragon Lady".:ack2:

    When I park my bike for a few hours, fuel automatically siphons to partially fill both tanks without leaking. When I don't want this to happen, I simply shut the Happy Time tank's petcock.

    I also bought a small electric fuel pump from ebay:

    A Whizzer battery and push-button switch will be more reliable in filling both tanks. Valves mounted atop tanks will allow me to fill them individually.

    These are the valves:
    Last edited by a moderator: Jun 6, 2009
  16. buzbikebklyn1

    buzbikebklyn1 New Member

    WWW>KIKKER5150.COM, small style "sportster" gas tanks. $90 in flat black, and it does away with the Mickey Mouse flandge seam on most kit tanks and holds 1 gallon, not that you HAVE to fill it up that much.
    Its got better mounts, a top mounted vented gas cap and a quality fuel valve.
    And it looks to friggin cool!
  17. 5-7HEAVEN

    5-7HEAVEN Guest

    Well, the self-tapping screw to plug the vented cap works. :devilish:

    It's been two weeks, and the caps never leaked a drop, even when gas is filled past the cap.:detective:
  18. SirJakesus

    SirJakesus Guest

    What about the fuel line grommet? Mine leaks a bit on my newer mits with the 30oz tank from staton. I was going to silicone the sucker until I read the label and it said "not to be exposed to gasoline" *sniffle*
  19. 5-7HEAVEN

    5-7HEAVEN Guest

    My grommets probably leak a little bit of air due to normal shrinkage. Maybe the engines are venting from there, since the caps are plugged.

    Mine hasn't leaked gas from the grommets because the siphoning from the reserve tank doesn't fill the engine tanks to their maximum.

    I just installed a 12-volt electric fuel pump to fill both engines' tanks. I'll make sure I don't fill to max.:detective: