Wiseco 455M05200 Classic Forged Piston Kit +2mm 52mm Oversize for Yamaha YZ100

The Wiseco 455M05200 is a classic forged piston kit designed as a high-performance replacement for the Yamaha YZ100 (1976–1983). Featuring a +2mm oversize 52mm bore, this kit is built for engines that have been bored out beyond the standard diameter, restoring proper tolerances and delivering reliable top-end performance.

Wiseco forges each piston from high-silicon aluminum alloy, a material chosen for its superior strength-to-weight ratio, excellent thermal conductivity, and resistance to wear under high-heat, high-RPM two-stroke conditions. The innovative piston skirt geometry reduces friction and side-loading while maintaining proper ring seal, translating to improved horsepower and throttle response.

Key Features:

• Forged high-silicon aluminum alloy construction for maximum strength and durability
• 52.00mm bore diameter — +2mm oversize over the standard 50mm bore
• Optimized piston skirt design for reduced friction and enhanced power output
• Complete kit includes piston, ring(s), wrist pin, and circlips
• Manufactured in the USA by Wiseco — an industry leader in forged pistons
• Oversize piston — cylinder boring or re-sleeving is required for proper fitment

The Wiseco 2047CD code identifies this as part of Wiseco's classic forged piston series for vintage two-stroke motocross applications. This kit provides everything needed for a complete top-end rebuild, making it an ideal choice for restoring or upgrading a vintage YZ100 to race-ready condition.