Whats up with these gas tank caps?

Discussion in 'Motorized Bicycle General Discussion' started by ran49, Apr 3, 2008.

  1. ran49

    ran49 New Member

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    Well they do keep the mice out.Aside from that not much better than a rag stuffed in there.I realize the tank needs venting but I think I might get another 10 miles a gallon if I wasn't sloshing it all about.I thought about stuffing the hollow can that extends down from the lid with air filter element but that would just create a mess when you removed it.
    Starting to look like a good excuse to make a custom tank.Any good source for a tank cap and threaded fitting?Thanks,Ron
     
  2. Pablo

    Pablo Master Bike Builder & Forum Sponsor

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    Yeah I feel like a rolling Molotov cocktail..........and you would think as a homo sapiens I wouldn't fill the thing all the way full the next time!

    Custom tank = nice!
     
  3. paul

    paul Active Member

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    i got a gallon tank from motorbike mike. i dont fill it all the way so not having gas come out. if i could be more careful filling it i would be all set lol
     
  4. ran49

    ran49 New Member

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    Checking around for gas tank fittings I found out that along with a cap you would need a "female boss" well a man shouldn't have to search too far to find one of those!LOL,Ron
     
    #4 ran49, Apr 3, 2008
    Last edited: Apr 3, 2008
  5. Ilikeabikea

    Ilikeabikea Moderator
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    If you can't find one just let me know. I can tell you where to get one.............rotflrotfl
     
  6. ran49

    ran49 New Member

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    Ilkieabikea
    Maybe,could you post a pic in the Swap Shop.Ron
     
  7. Ilikeabikea

    Ilikeabikea Moderator
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    I asked the "female boss" about posting a picture in the swap shop. Oh well I enjoy sleeping on the couch in the den..........................:-||
     
  8. deacon

    deacon minor bike philosopher

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    I wonder if you couldn't just take the cap we have to the auto parts store and try matching it up with one that isn't vented. I have had lawn mower with those off set vent holes Joe mentioned. Gas didn't slosh but it always smelled of gas when the weather changed.
     
  9. Ilikeabikea

    Ilikeabikea Moderator
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    I just always leave mine about an inch or so below the neck and don't have any trouble with sloshing........................
     
  10. RedB66

    RedB66 New Member

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    After several ruined paint jobs and the discovery of gas resistant clear coating I fixed my problem by adding another gasket. I made it from a heavy duty inner tube. I tried placing it behind the original to take up some space and get a better seal but discovered that it worked best by placing the additional gasket on top of the existing one. I haven't had any problems with venting.
     
  11. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    What I did was to drill a very small hole with my pin vise drill on the top side of the cap (cant see it). Then I drilled another in the middle underside of the cap.

    I think what happens is that the gas sloshes and also gets warmer and then when it splashes up on the cap gasket, the pressure tends to force it out. When I vented my tanks, I never had a problem again.
     
  12. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    I drilled a hole in the top center of both my caps. What was happening on my bike was the fuel would slosh and the engine would warm it and it would pressurize the tank a little, then when the fuel splashed up near the filler neck, it was forced out around the crappy gasket.

    I haven't had any problems since I drilled them.
     
  13. deacon

    deacon minor bike philosopher

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    Great idea, I think I'll make one and put it on today. I don't have a problem because my tank is at a funky angle. But one never knows what will happen on any given day.

    Gas is really known to expand in the tank. They used to say fill your car first thing in the morning and you get more gas because it is more dense. It will expand as the day goes on. So I wouldn't fill mine when its cool then store it. Fill it then ride it I think would be best.

    That is true about the expansion I have filled my car then driven home a few blocks left it all day and found a puddle at noon.
     
    #13 deacon, Apr 4, 2008
    Last edited: Apr 4, 2008
  14. ran49

    ran49 New Member

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    Just to be sure is this the same cap you guys are talking about.Notice vent hole inside rim(very bottom of pic).It seems to allow gas to pass through and around any seal you might have with "boss".Ron
    [​IMG][/IMG]
     
  15. Pablo

    Pablo Master Bike Builder & Forum Sponsor

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    I gotta say - my cap is different. No vent hole like that. Still leaks.
     
  16. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    No vent holes in mine.
     
  17. SeattleMike

    SeattleMike New Member

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    Maybe I'm lucky, but my cap and tank have been great. I fill mine up, no sloshing. Today I had to take the tank off to install a new exhaust pipe, and I even dropped it when it was full of gas, it didn't hit the floor because the fuel like was still connected so when I dropped it, it dangled from the carburetor. I freaked out, when I realized I dropped it and it yanked by the fuel line, I totally expected gas to leak out all over me, the bike, and the soft wooden floors of my shed, but not a single drop came out! It was amazing. It seems to vent fine too, but the weather has been cold since I've gotten it. Also, I always use a funnel when I put gas in the tank, to make sure I don't get a drop on the tank when I fill it up.
     
  18. Dave31

    Dave31 Moderator
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    For three years not one drop has leaked from my cap. I fill it all the way to the top, no problems.
     
  19. Pablo

    Pablo Master Bike Builder & Forum Sponsor

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    I think I will see if I can get a new cap.......
     

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