Wiseco PK1194 56.0mm Pro-Lite Piston Kit 2002 Yamaha YZ125

The Wiseco PK1194 is a Pro-Lite forged piston kit designed for the 2002 Yamaha YZ125, featuring a 56.0mm bore diameter and includes a top-end gasket kit for a complete rebuild solution. Wiseco pistons are forged entirely in-house in the USA, giving the company full control over every stage of manufacturing — from raw bar stock to final skirt coating.

Key Features:

• 56.0mm (797M) bore diameter for a precise fit in the 2002 Yamaha YZ125
• Pro-Lite forged construction — lighter than standard forgings while retaining superior strength
• Includes top-end gasket kit for a complete, ready-to-install rebuild package
• USA forged — all pistons and forge tooling produced in-house for consistent quality control
• Skirt coating applied for reduced friction and improved wear resistance
• Optimized strength-to-weight ratio to maximize performance without added mass
• Condensed, aligned grain structure delivers superior mechanical properties, impact resistance, and fatigue resistance compared to cast alternatives
• In-house dyno tested — developed through rigorous R&D including advanced shapes, coatings, and components

Unlike cast pistons — which are brittle, lack directional grain structure, and risk catastrophic failure under peak loads — Wiseco forgings are engineered to withstand the extreme heat cycles, high RPM, and mechanical stress of 2-stroke motocross racing. The PK1194 is a direct-fit replacement that restores lost compression and power, making it the go-to choice for YZ125 top-end rebuilds.