FITS THE FOLLOWING ORIGINAL ENGINES: CT90'S K5, K6, AND 1976 TO 1979 ALL YEARS OF ST90'S ATC90'S WITH A ENGINE SERIAL NUMBER'S LARGER THAN 1113934 OR ABOUT 1972 AND NEWER "DIY" NEW TYPE OHC90 HEAD/CYL 120cc "SLEEPER" STROKER CRANK CORE KIT READ FITMENT CAREFULLY (273L/253K/335T) 273L/253K/335T$149.95 PLEASE CLICK AND READ THIS BEFORE BUYING CRANK PIN INSTALL INSTRUCTIONS PIN ARROW POINTS UP BOTTOM END ROD CLEARANCE/GAP .004" RING INSTALATION SEE PIC / PISTON TO CYLINDER CLEARANCE .001" TO .002" THE CHARACTER SIDES FACE TO THE TOP OF THE PISTON DOME MAKE SURE THE GASKET POINTS DON'T GET IN THE WAY OF THE STUD HOLES FIY FIY FIY