All pistons are heat treated with a T-5 hardening and tempering cycleAll piston skirts are coated with a high-tech Molybdenum Disulphite coating for faster break-in time and increased piston lifeCast piston kits are gravity cast aluminum alloy (not forged) with 18% silicone content, which produces an extremely light but very strong pistonBig Bore pistons increase engines displacement, torque, and peak horsepowerReplica pistons and all rings are OEM replacements+0.50mmStandard compressionDisplacement: 100ccCylinder Diameter: 53mmPiston Diameter: 52.940mm