Hi:

     I just assembled a Fox .35 Stunt from assorted parts and I find that the cylinder is a shrink fit in the crankcase.  The piston is a very tight fit in the cylinder.  I used a p&c that I new was  great fit into a new crankcase. I cleaned all of the burned on residue from the outside of the cylinder to aid fitting it to the case.  I left the burned on castor residue on the piston.  Perhaps I should remove the p&c and remove the castor residue from the piston.  I left it on to help form a good seal. Perhaps, it should be removed as he fit of the p&c is vey tight. I have been running the engine in a rich mode hoping that it would form a good p&c fit.

     Any suggestions?

                                                                                                              Tia,

                                                                                                              Frank McCune

Possible muffler clamp distortion going on here.