exhaust gasket keeps blowing out

Discussion in 'Motorized Bicycle Trouble Shooting' started by tdsears0627, Sep 10, 2013.

  1. tdsears0627

    tdsears0627 New Member

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    I have an issue with the exhaust gasket keeps blowing out I replaced the stock studs with Allen head bolts I am using the voodoo expansion chamber exhaust, I put lock tight on the bolts and tightened the bolts until they wouldn't go any more and they are not bottoming out either ,

    I guess my question is has any one else had this issue and how did you fix it, and is there a metal exhaust gasket out there or some other material than the cardboard type:-||:-|| that came with it
     
  2. 2door

    2door Moderator
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    Remove the exhaust and try this. Clean the gasket surface of the exhaust flange and 'paint it' with a magic marker or paint. Now rub it against a sheet of sandpaper laid on a known flat surface, glass is best, and you'll see the high and low spots that must be removed to get a good gasket seal.

    The welding process when the flange is welded to the pipe warps the flange so you won't have a good flat surface where the gasket is supposed to seal.
    Sand or grind the flange flat and see if this doesn't help preserve the gasket.

    Also the gasket material needs to be something better than comes in the kits. I like to use gasket material made for exhaust applications and is at least 1/8" thick. Torque the fasteners to about 60 to 80 inch pounds then check the torque again after the engine has reached operating temperature a couple of times. Using gasket sealers is not necessary.
    Longer or heavier pipes also need to be supported. Don't rely on the exhaust manifold fasteners only to keep the pipe secure.
    Good luck.

    Tom
     
  3. crassius

    crassius Active Member

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    after checking that mating surface is flat, also check that whatever you're using to support the weight of the exhaust is not pulling the pipe crooked on the gasket

    also check obvious things like engine is loose and pulling away from pipe
     
  4. SuedePflow

    SuedePflow New Member

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    I'll bet your flange isn't flat. Between being poorly cut from cheap, thin material, and then having a tube welded to it, my flange was far from flat when I got it. I ran it on a belt sander until it was flat and even across. And its been sealing with the same gasket since.
     
  5. paintgun

    paintgun New Member

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    I just noticed today I had an exhaust leak on the bottom side of the connection to the engine. Thinking it might be either a warped flange or the cheap gasket burned through. Will check for trueness of the flange when I get a chance.
     

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