how to get cylinder over piston

Discussion in 'Motorized Bicycle General Discussion' started by fischer550, Apr 8, 2014.

  1. fischer550

    fischer550 Member

    Mar 24, 2014
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    Hey guys, so I took the cylinder off the piston, and for the life of me i cannot fit the cylinder over the piston/rings, can someone tell me how? thanks
  2. GearNut

    GearNut Active Member

    Aug 19, 2009
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    I am assuming that you are referring to a 2 stroke engine.
    There are small locating pins in the piston ring grooves. They prevent the piston rings from rotating around the piston and the piston ring ends from getting snagged on a cylinder port.
    You need to ensure that the locating pins are centered in the piston ring end gaps.
    Carefully use your fingernails to compress each ring into the piston ring groove as it slips up into the cylinder. Use pre-mix oil, very lightly applied, to help things slip in easier.

    Here is an excellent tutorial from Norman, Lord Vader on how to rebuild the top end.
    Pay close attention to posts # 10 and #11 for ring end gap/ locating pin info and a handy home made tool to help hold the piston for you as you slip the cylinder over the piston.

    Above all, take your time and never force the cylinder on with a hammer or other striking object.
    #2 GearNut, Apr 8, 2014
    Last edited: Apr 8, 2014
  3. Henshooter

    Henshooter New Member

    Feb 10, 2014
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    Very informative cheers gear nut

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