THIS PISTON IS SPECIAL FOR OUR 120CC STROKER CRANK KIT AND WON'T WORK AS A BIG BORE PISTON FOR ANYTHING IT IS SHORT DOMED AND SHORT SKIRTED 253K @ RING INSTALATION SEE PIC / PISTON TO CYLINDER CLEARANCE .001" TO .002" @ THE CHARACTER SIDES FACE TO THE TOP OF THE PISTON DOME