Wiseco PK1345 Pro-Lite 2-Stroke Piston Kit 54.5mm Bore for YZ125

The Wiseco PK1345 Pro-Lite Piston Kit is a complete top-end rebuild kit featuring a forged aluminum piston at 54.5mm (0.50mm oversize) bore diameter — part number 797M05450. Engineered and manufactured in the USA, this kit delivers everything needed to properly overbore or rebuild the top end of a 2003–2004 Yamaha YZ125 two-stroke engine.

Key Features:

• Forged aluminum construction — high-silicon alloy provides superior strength, lighter weight, and improved heat transfer compared to cast alternatives
• CNC-machined Pro-Lite design — optimized cam shape and piston skirt profile for maximum horsepower, torque, and throttle response
• Dedicated forging — purpose-built for the YZ125 engine to deliver an optimized strength-to-weight ratio
• Complete kit — includes forged piston, piston ring, wrist pin, circlips, and top-end gasket set
• 0.50mm oversize bore — ideal for cylinder overbore or worn-bore rebuilds
• Made in the USA — engineered, forged, and machined at Wiseco's facility in Mentor, OH

Wiseco PK piston kits include a complete top-end gasket set, making this a true one-stop solution for your rebuild. The Pro-Lite series is Wiseco's proven, all-purpose 2-stroke forged piston line — delivering the reliability and performance that has made Wiseco a trusted name in dirt bike, motocross, and powersports applications for decades.