Prox Full cast size A Piston kitRef : 241028DA / 1095503001

The PROX cast piston (Manufacturer's ref: 01.2321.A) is designed for motocross riders looking for a robust and reliable replacement part. Machined from a specific aluminium alloy, it adheres to the manufacturing processes commonly used by manufacturers and offers an interesting compromise between strength and bore retention. Its skirt features a Mos2 treatment to reduce friction with the cylinder.

• Diameter: Ø 66.35 mm (oversize letter: A)
• Compression: Standard — domed head with machining for reeds and intake passage
• Manufacturing: cast aluminium piston
• Patented surface treatment on the skirt (Mos2) to reduce friction
• Ideal as an equivalent replacement for motocross use
• Associated parts kit: rings 260137 / pin 031182 / circlips CP1812 / needle cage 400403

This piston is aimed at motorcycle preparations where reliability and ease of installation are paramount. Suitable for YAMAHA YZ 250 (2026), FANTIC XX 250 (2026), and SUZUKI RM 250 (2008) models — please check the exact compatibility with your bore before installation. PROX product, a reliable reference for the maintenance and refurbishment of motocross engines.