Home Forums Shifter Karts CR125 Help Needed-Loading Up

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    • #28563
      Sanford Mitz

      I have a CR125 with a tough problem. Been racing shifter since 1996 and have owned several CR125’s. The one in question will not run clean out of the pits and takes two laps to clear out.

      Once clear, it runs fine.

      Jetted all over the map- currently 170 main, 50 Pilot, DGJ needle at mid clip

      All of the usual bases have been covered. Fuel system completely gone over, double vented the tank. replaced the lines. Two different top ends. two different carbs, coils, leads, etc.

      I’m looking for the out of ordinary. Porosity in the case or a crack that closes up with heat. Have not replaced the pipe, silencer, stator, or CDI.

      Ready to put it on the shelf and try another one. Give me your WAG.


      Sanford Mitz



    • #30997
      Joey Kolbe

      Hey Stanford – Are you using a pump around delivery system?

    • #31011
      jack lachut

      have you checked the reeds?

      how is your air bleed screw set on the carb?

      • #31024
        Sanford Mitz

        Thanks for the replies. The actual adventure on this engine took us through the usual, carbs, intake items, coils, stators, and even a second top end., etc. Finally in a start over mode, a pressure check of the case revealed that it was losing about 1#/minute. I split the case and replaced the center gasket. Also replaced the crank seals at the time. Post reseal, the pressure check dropped less than 1# in 30 minutes. Engine runs great now.

        PS-It had just been rebuilt.

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