Quick question

Discussion in 'Motorized Bicycle General Discussion' started by dreadlord69, Sep 1, 2012.

  1. dreadlord69

    dreadlord69 New Member

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    Ok, I am doing a rebuild, but the gasket that sits below the cylinder was lost. Which brings me to my question can I use a liquid gasket there? will it hold to the compression on an 80cc Chinese happy time. Any replies would be appreciated.
     
  2. paul

    paul Active Member

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    i would probably get gasket material and a razor blade and cut my own gasket. i only tried the liquid gasket once and it made a heck of a mess
     
  3. Ludwig II

    Ludwig II Well-Known Member

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    It's possible to lap the joint in by careful use of grinding paste between the barrel and cases, so allowing you to use a gasket paste, but you'd have to be sure no grit went inside the engine for a start and clean it all off after doing the job. Then there is also the question of altering transfer port timing because the barrel will sit a small but measurable bit lower than it did.

    You don't have to have the part from your supplier though. There is a gasket material supplier in most towns that will sell an appropriate sheet you can cut to fit.
     
  4. Ludwig II

    Ludwig II Well-Known Member

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    But don't even think about corn flake packets.
     
  5. CroMagnum

    CroMagnum Member

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    A new base cylinder gasket costs around $3. So instead of spending all that money, you want to Mickey Mouse something that will probably leak? :confused:
     
  6. Ludwig II

    Ludwig II Well-Known Member

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    Not necessarily Mickey Mouse, I have friends who do all that hand finishing as a matter of course, but as you say, why bother with learning the hard way when bits are cheap?
     
  7. tooljunkie

    tooljunkie Member

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    for me,the need to cut gaskets is quite often,working on obsolete things.
    that and getting gaskets for these things doesent involve a ten minute drive to the local parts store.
    i have never had any trouble with my hand forged gaskets.
    the trick is to use the correct material for your project.
    when purchasing,explain you need fuel resistant gasket material.
    i never checked,but i'm sure there will be something on youtube for cutting gaskets.
    i could go on about various methods,but it would take a lot of typing.
    if it doesent exist,i will put something together.
     
  8. 2door

    2door Moderator
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    I'm waiting for someone to tell him to J-B Weld it. :)

    Actually I've done several using the method suggested by Ludwig. The gasket surfaces must be clean and flush with each other and a gasoline compatible sealer used. I've never had one fail yet. The difference in cylinder height with or without a gasket isn't enough to worry about compression or port timing. Not on these little Chinese 2 strokes.

    Tom
     
  9. Ludwig II

    Ludwig II Well-Known Member

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    Try it an a 4 stroke with a lumpy camshaft.
     
  10. 2door

    2door Moderator
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    We're not talking about modified 4 stroke engines.
    The OP's question and the discussion is about Chinese 2 stroke bicycle engines. And I stand by my statement regarding them.

    Tom
     
  11. Ludwig II

    Ludwig II Well-Known Member

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    I know this. I've had East European 2 strokes that needed to phone the cylinder head, the pistons were that far away.
     

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