Piston Yz144 Race 23335BPiston Kit Cast Big Bore for 2 StrokeThe piston is heat treated with a T 5 hardening and tempering cycle The piston skirt is coated with a high tech Molybdenum Disulphite coating for faster break in time and increased piston life Cast piston is gravity cast aluminum alloy (not forged) with 18% silicone content Big bore piston increases engine's displacement, torque, and peak horsepower Piston kit includes piston, rings, wrist pin and circlips Kit