Athena P400485100008 Standard Bore Cylinder Kit (54mm, 125cc) Premium 2 Stroke Top End Rebuild Kit with Forged Piston & Gaskets, Compatible with Yamaha YZ125 2001 2004 Orbit Sander Power Tools This durability translates to fewer Holeshot This durability translates to fewer replacements and more miles of riding enjoyment 9 horsepower permanent magnet motor and dynamic and mechanical braking system ensure exceptional control and durability Entirely cast from high grade aluminum and treated with a specialized Motor Nicksil (Nickel Silicon) coating and a specific high tightness gasket set—allowing you to drop compression losses and refresh your engine without requiring any machining or structural engine modifications to your factory crankcase