Throttle seems to be sticking

Discussion in 'Motorized Bicycle General Discussion' started by bobs hog, Sep 26, 2010.

  1. bobs hog

    bobs hog New Member

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    Any ideas? Seems as when I ride my bike with throttle opened up for a period of time then let off it takes some time for the idle to drop down??
     
  2. GearNut

    GearNut Active Member

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    Although that sounds more like an air leak, you can verify or eliminate the slide as the problem by removing the air cleaner and looking down the throat of the carburetor while working the throttle grip. Use a mirror if necessary. See if it is in fact getting held up in the slide bore of the carburetor. Usually if this happens though, the engine will just scream at full throttle or close to it.
    This is just step one in the diagnosis. Check it out and get back with us, ok?
     
    #2 GearNut, Sep 26, 2010
    Last edited: Sep 26, 2010
  3. bobs hog

    bobs hog New Member

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    When you say air leak one problem comes to mind. I had a hard time fitting the carb to the motor it was very tight. I noticed the carb has slots in it where the clamp goes if the carb didnt seat all the way can this be the problem? (maybe sucking in air)
     
  4. GearNut

    GearNut Active Member

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    Absolutely!!!

    Some folks will recommend using an o-ring the same size as the intake manifold stuffed down into the carb spigot (mounting hole) to seal the intake.
    I personally cannot recommend this in any way, shape, or form. Using the wrong type of rubber that the o-ring is made of can cause the o-ring to swell, get soft, and eventually get sucked into the engine.
    When in a pinch, I like to use a product called Seal-All or RTV silicone black or copper.
    Some vendors also sell a intake manifold with a groove machined into it to accommodate an o-ring. Check out Pirate Cycles for one. IMHO this is the only reliable way to o-ring a manifold, and it is also the best way to seal the carb mount to the manifold.
    If you are skilled with a hack saw, you can cut your own groove in your current manifold and use an o-ring from a kit sold at Harbor Freight. Just be sure to get the correct rubber that is gasoline and oil resistant. It is called Buna-N. Silicone o-rings will also work if you can find them, they usually are a light blue color.
     
  5. bobs hog

    bobs hog New Member

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    Thanks so much I'll give it a try!
     
  6. Blackrain2012

    Blackrain2012 New Member

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    HAD the same problem

    wrap some GAS grade teflon tape around the intake BEING CAREFUL not to get it into the manifold. then put the carb on. it should be a tight fit.

    or

    CLEAN THE MANIFOLD REALLY GOOD and sand it do its not so slippery, then put a few wraps of electrical tape around it. NOT DUCT TAPE. im talking about the little black roll that is about a half inch wide. This is what i did and it fixed my problem in no time!
     
  7. bobs hog

    bobs hog New Member

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    My problem when installing the carb was the carb was very tight sliding on to the manifold. I dont even think I was able to get on all the way to the stop. It went on barley past the slits cut into carb where the clamp goes on. Think I can sand down the manifold tube??
     
  8. 2door

    2door Moderator
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    You could take some material of the outside diameter of the intake manifold and if its really that tight you can also ream out the carburetor...but just a little and do it carefully. Clean everything well after you do any sanding or grinding.
    I have to disagree with the electrical tape suggestion. It will eventually get attacked by the gasoline and make a gummy mess that could get into your engine. Gear Nut's suggestion about using Seal All or a gas resistant sealer is the best method.
    As for the original question, if you're not sure what is binding/sticking, I always suggest to disassemble the throttle cable from the twist grip and carb and try each part seperately to find out what isn't moving freely. Lube the cable and where it's attached to the twist grip and make sure there is no plastic flashing in the cable groove in the grip. Overtightening of the cap where the cable enters the carb or the carb to the manifold can also cause a warp that will bind the slide (barrel) inside the carb.
    Please let us know what you find.
    Tom
     
  9. bobs hog

    bobs hog New Member

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    thanks guys for the help. I sanded down the intake tube to fit the carb all the way and seems fine now.
     
  10. GearNut

    GearNut Active Member

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    Congratulations on your repair!
     

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