ProX Piston Kit 66.37 mm for Suzuki RM250 and Yamaha YZ250/YZ250X (01.2321.C)

The PROX 01.2321.C Piston Kit is a precision-engineered OEM replacement solution for select Suzuki RM250 and Yamaha YZ250/YZ250X two-stroke motorcycles. Manufactured in Japan, this piston kit is designed to restore dependable engine performance and provide a reliable fit for compatible applications. Its 66.37 mm piston is developed for riders, mechanics, and powersports professionals seeking replacement components built to OEM-level standards.
The piston is cast from a high-silicon-content aluminum alloy that meets or exceeds OEM specifications. This material provides a strong foundation for consistent operation under demanding riding conditions while supporting the durability expected from a quality replacement piston. PROX then CNC-machines the component to extremely close tolerances, helping promote accurate installation, proper ring seating, and dependable engine function when installed according to manufacturer procedures.
Each PROX 01.2321.C kit includes the piston, ring kit, wrist pin, and circlips, providing the essential components needed for a comprehensive piston replacement. The included parts help simplify installation and reduce the need to source individual components separately. Always verify motorcycle year, model, bore requirements, and service specifications before installation to ensure compatibility.
Feature: Manufactured in Japan for consistent production quality. Feature: OEM replacement design for select Suzuki RM250 and Yamaha YZ250/YZ250X applications. Feature: Cast from high-silicon-content aluminum alloy meeting or exceeding OEM specifications. Feature: CNC-machined to extremely close tolerances for a precise fit. Feature: Kit includes piston, ring kit, wrist pin, and circlips. Feature: Piston size is 66.37 mm.

Features:

• Manufactured in Japan for consistent production quality

• OEM replacement design for select Suzuki RM250 and Yamaha YZ250/YZ250X applications

• Cast from high-silicon-content aluminum alloy meeting or exceeding OEM specifications

• CNC-machined to extremely close tolerances for a precise fit

• Kit includes piston, ring kit, wrist pin, and circlips

• Piston size: 66.37 mm

Ships from Parts Unlimited.