vacumm leak???

Discussion in 'Motorized Bicycle General Discussion' started by wes, Oct 1, 2009.

  1. wes

    wes New Member

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    So i think i have a vacumm leak some where, when i pull in the clutch to stop at a light the engine revs and it takes a sec to idle down, when it does idle down its to low, so i adjust it to where i want it, and when it comes to stopping again it idles way high, i know that when i choke a warm motor it cuts the air intake which results in killing the engine, but this one idles higher when i choke it warm, i have rtv on the intake and the carb and dont beleive this is where it is, if anyone has had this problem i think it is coming from the carb slide cap or ??? I bought a can of carb cleaner this morning and will attempt to spray it once it cools from my recent ride, this motor still runs really strong and smooth so what ever it is has to be very small..wee.
     
  2. Junster

    Junster New Member

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    The higher idle when you choke is a sure sign of a leak. Suggest you use wd-40 to test things. With the choke open and the idle turned up some spray around the intake mount, then the carb mount, then around the cylinder base. The motor idle should slow when you hit the leak. If you find no leaks lower the clip on the needle one notch. A to lean condition can cause that too.
     
  3. Venice Motor Bikes

    Venice Motor Bikes Custom Builder / Dealer/Los Angeles

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    I spray starting fluid around the engine to find a air leak.... The engine will start to rev up when you spray it onto the leak!
     
  4. Kevlarr

    Kevlarr New Member

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    Check the intake where it mounts to the engine, someone had this problem the other day and he found that intake was cracked at one of the mounts.
     
  5. Dave31

    Dave31 Moderator
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    The cylinder base gasket will also cause a vacuum leak. I also had a vacuum leak on the carb slide cap, some Teflon tape should take care of that.
     
  6. wes

    wes New Member

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    How did you fix the cylinder base gasket? I think if that is what is wrong with mine i will ride it till it dies
     
  7. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    To fix the base gasket, replace it or take it off, coat both sides with a heavy coat of aluminized spray paint and re-install.
     
  8. 2door

    2door Moderator
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    Another place you'll want to check for leaks is the crankshaft seals. The magneto side is the most common to fail. The factory sometimes doesn't get the seal pressed in as far as it is supposed to go and the magnet rubs it and screws it up. Spray around the mag cover and where the wires exit the case. You'll see the difference in rpm if that seal is bad.
    Tom
     
  9. wes

    wes New Member

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    so i sprayed it down with the carb cleaner and it seemed to lower the rpms around the intake to carb mount, thats funny cause i thought carb cleaner would rev the motor but aperantly not, so i put some new rtv on it and hopefully this will work, thanks for the replys,
     
  10. Venice Motor Bikes

    Venice Motor Bikes Custom Builder / Dealer/Los Angeles

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    Starting fluid will rev the engine!
     

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