Overheating Engine

Discussion in 'Motorized Bicycle General Discussion' started by Mopedamauter79, Jun 11, 2008.

  1. Mopedamauter79

    Mopedamauter79 New Member

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    Just wondering what could be the reason for the engine to overheat and how to cool it off. I have CH80 Engine if that means anything. I know it was overheating as I can only idle and rev the engine when it's really hot. That and I could feel the heat through my pants. It acts up when it's to hot. It would putter like it does when say your going to slow and it's about to stall due to a very slow speed. Another way to describe it is the sound it makes when you forget the to switch the gas valve to the one position and it's starving for gas..

    I hope I made this clear enough.
     
  2. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    An air leak will make it run poorly AND get really hot, next step- oblivion.
     
  3. Ritchie

    Ritchie New Member

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    Air leaks cause lean conditions which kills the 2 strokes. Same goes for incorrect carb settings. If in doubt, run rich.

    There are guides on this site (or links) to read your fuel/air mix from your spark plug colour.
     
  4. Dave31

    Dave31 Moderator
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    Yes, you are running lean to cause overheating, vacuum leak at manifold or at carb. Or the carb need's to be looked at.

    I suspect your plug is white? Here is a chart of plug's

    [​IMG]
     
  5. Mopedamauter79

    Mopedamauter79 New Member

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    Carb does not appear to have any leaks and I retightened it to make sure. The spark plug I have no means to take off. I can't find the tool that came with the engine kit. Where can I get one in Ontario ?
     
  6. Ritchie

    Ritchie New Member

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    Any auto store, canadian tire etc. home depot/ rona (in the lawn mower section). There are generally 3 sizes, you want the 3/4 inch one (if yours is a Z4C plug), I'd say look at the lawn mower sections first.

    Just make sure you can exchange it if you need a different size.
     
  7. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    I would definitely have a look at the plug, it will tell you a lot.
     
  8. Mopedamauter79

    Mopedamauter79 New Member

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    The little metal piece that creates the gap is grey and the rest of spark plug is brownish black.
     
    #8 Mopedamauter79, Jun 12, 2008
    Last edited: Jun 12, 2008
  9. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    That's a little lean...look for an air leak, or adjust you needle clip down one notch and check it again.
     
  10. Mopedamauter79

    Mopedamauter79 New Member

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    How do I check for an air leak ?
     
  11. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    The best thing to do is remove the intake manifold from the cylinder and coat both sides of the gasket with RTV sealer....make sure you take the gasket off and coat both sides of it then re-install it.

    Make sure the carb is fully on the manifold and tight. Check your head fasteners as well. (four nuts on the top of the engine surrounding the plug). Just snug them down, don't over do it.
     
  12. stude13

    stude13 New Member

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    you can start the motor, let it idle, then squirt some starting fluid ( wd40 ) at the junction of carb tube and engine, try wiggling the carb at the same time. if there is a leak the engine will rev up.
     
  13. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    ...or want to quit, depending on what you use....either way it will tell you if you have a leak without removing anything.
     
  14. Saddletramp1200

    Saddletramp1200 Custom MB Buiilder

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    The safest way is a spray bottle with water in it. With the engine running spray around the carb. NOT into the air cleaner! If there is an air leak it will bog down. (c)
     
  15. Mopedamauter79

    Mopedamauter79 New Member

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    I have ran the engine in the rain before and it never bogged or stalled. I will try out the suggestions when I feel better. Took a nasty wipe out yesterday afternoon.
     
  16. Mopedamauter79

    Mopedamauter79 New Member

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    The carb has no gasket at all and that is probaly the source of the air leak. I'm transfering the motor to a new frame that's smaller tubbing so it will be easier to install. The reason for this is the back end of the frame is not even. The back wheel wont line up properly at the bottom and the top by the brakes. If it's lined up at the bottom it's off center at the top. I tried different wheel's with the same result..There doesn't seem to be any damage to the frame that I can see...
     
    #16 Mopedamauter79, Jun 18, 2008
    Last edited: Jun 18, 2008

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