Can a China Girl be Bored out to fit a 52mm Piston?

Discussion in '2-Stroke Engines' started by Leroybrown420, Jul 1, 2015.

  1. Leroybrown420

    Leroybrown420 Member

    Can a China Girl's cylinder head be Bored out to fit a 52mm Piston? Just out of curiosity, can this be done?

    If so, what are the pros and cons?

    If not, why?

    Last edited: Jul 1, 2015

  2. jaguar

    jaguar Well-Known Member

    You might be able to get away with it but then you'd have to replate the inner cylinder which is costly.
    But if you want to perfect this setup then that's the way to go, a good piston/rings and a replated cylinder. The standard rings have too much ring end gap which loses compression, and the lining wears off if you increase the compression which is necessary for more power.
    send them the piston/rings also so they can hone it down till the ring end gap is correct.
  3. crassius

    crassius Well-Known Member

    also, a steel sleeve could be installed allowing some modification of port timing
  4. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    It has already been done with a 50 mm piston and iron liner.

    How much would you pay for this?

    Yes, you can sorta buy one now.......

    PS: The correct word is cylinder, not head. You don't bore heads out.
  5. Leroybrown420

    Leroybrown420 Member

    I wouldn't pay much, I'm a total cheap ass. I'm after the cool factor with no budget. I do have a new "cylinder" head that was machined wrong. The piston drops in the top but will not make a turtle head (tapered). Was trying to find a purpose for it greater than hold down my parts bin.

    Was there any noticeable difference in performance on the 50mm piston? Did it run hotter?
  6. butre

    butre Well-Known Member

    there's a dude in Miami working on a big bore kit
  7. Fabian

    Fabian Well-Known Member

    I have always hoped that someone would manufacture a big bore top end cylinder kit for these engines
  8. butre

    butre Well-Known Member

    Mark Clyde Stewart sells 50mm big bore kits for $150. I don't know if it's just a jug or piston, wrist pin, and rings are included.
  9. Fabian

    Fabian Well-Known Member

    What are Mark Clyde's contact details, and does he have a web site?
    I want his 50mm big bore kit.

    Actually i want his 60mm big bore kit.
  10. butre

    butre Well-Known Member

  11. HeadSmess

    HeadSmess Well-Known Member

    take it to a machinist with a length of cast pipe with an id and od suitable, and give him a bottle of good scotch or something... would take all of 3 hours with the material and equipment on hand.
  12. butre

    butre Well-Known Member

    if I had a lathe of my own I'd do up one for a bottle of talisker any day of the week