Wiseco 4865M09600 Forged Piston Kit Oversize - 96mm 1mm YFZ450

The Wiseco 4865M09600 is a forged piston kit designed for the Yamaha YFZ450, featuring a 96mm bore diameter (+1mm / +0.040" oversize) at standard compression. Engineered, forged, and machined in the USA at Wiseco's facility in Mentor, Ohio, this piston kit is built to deliver a precise fit for cylinders that have been bored oversize during rebuild.

Key Features:

• Forged Aerospace-Grade Aluminum: The forging process compresses and aligns the grain flow of the alloy, resulting in superior density, impact resistance, and tensile strength compared to cast pistons
• 96mm Bore (+1mm Oversize): Ideal for YFZ450 engines with cylinders bored 1mm over standard, restoring proper clearances and compression
• Optimized Strength-to-Weight Ratio: Dedicated forgings are designed to reduce reciprocating mass while maximizing durability under high-performance and racing conditions
• CNC Diamond-Turned Finish: Precision machining ensures consistent sizing and a surface finish compatible with cast iron, chrome, Nikasil, and boron composite cylinder bores
• USA Manufactured: Engineered and produced at Wiseco's Mentor, Ohio facility using 3D design techniques and finite element modeling
• Complete Kit: Includes piston, rings, wrist pin, and circlips — everything needed for a top-end rebuild

The 4865M09600 is the go-to oversize piston solution for YFZ450 engine rebuilds where the cylinder has been bored or re-sleeved to 96mm. Wiseco's exclusive forging process makes this the preferred choice for riders who demand performance and long-term reliability from their ATV engine.