Home Forums 250 Superkarts piston mod on 250 engines?

This topic contains 2 replies, has 2 voices, and was last updated by  nigel cooper 6 years ago.

  • Author
  • #5113

    nigel cooper

    An online cr125 rebuild manual mentions drilling 2 holes on the piston to assist in lubrication and reduction in wear.


    Does anyone do this on the 250`s  just wondering

  • #5134

    Ian Harrison

    Hi Nigel

    We don’t notice any difference with the holes drilled or not. The idea is that you get some extra cool mixture lubricating the port bridge.

    In my view your just as likely to get pulse-returned hot contaninated exhaust gas passing the other way when the piston is on the upstroke and crankcase pressure is negative.

    Best Regards


  • #5152

    nigel cooper

    Thanks Ian for the reply, (and the explanation)


    ps-Ill be posting a question in the  next few days regarding a comment you made a few years ago regarding cylinder ccs


    cheers nc


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