Gas Leak.

Discussion in 'Sportster Models' started by the kid, Aug 2, 2011.

  1. the kid

    the kid New Member

    I have a 1990 Sportster that I just got recently, I had to rebuild the engine on it (had a mechanic do it) I've got the bike now and I'm having an intermitent fuel leak problem coming out of the overflow on the carb. I have had two people look at it they say the carb is fine they will clean it and then a few days later the bike will start leaking again. This is only during start up and shut down most of the time. By leaking I mean tons of fuel coming out. Another thing I have noticed is that it seems that sometimes the fuel take hisses when I pull the cap off. When we rebuilt the engine the mechanic removed all the smog stuff and plugged the required hoses. Does anyone have any ideas?

  2. fin_676

    fin_676 Experienced Member Staff Member Moderator Contributor

    After a few years of use the rubber coating on the tip of the float valve needle hardens and fails to seal and fuel will flow out of the overflow of the carb
    The float needle needs to be replaced

  3. JBC2565

    JBC2565 Junior Member

    After doing what Brian said, I know a lot of sportster riders who shut the fuel off at the petcock when they get off the ride for the day.
  4. Bodeen

    Bodeen Well-Known Member Staff Member Moderator Contributor

    Not sure how your particular model vents its gas tank but that sounds like your problem. Some have a vacuum hose coming down in front of tank and under seat, some vent with by way of gas cap. At any rate when the fuel gets hot and expands, the resulting pressure build up has to have a place to go and in your case its through the carb. To much pressure for the needle and seat to hold back.
    Some one will be along that knows exactly how your model vents. Good luck with it and let us know what you find.


    Welcome to the Best on the Net too!
  5. glider

    glider Veteran Member

    You may have a vent line plugged when the mechanic plugged the smog equipment, you shouldn't get a presure release when opening the gas cap. The gas cap may be either the wrong one or not venting also. Lastly as Brian said, the float needle may need replacing.
    Try to give an accurate assessment of fuel leaking instead of "tons". Is it a few drops, a few ounces or the entire tank leaking out. It will help to asses the issue if you give accurate info.