PROX Piston Kit 01.2429.B — Yamaha YZ450F/WR450F 12.5:1, 94.97mm Bore

The PROX Piston Kit 01.2429.B is an OEM-quality replacement designed for Yamaha YZ450F models from 2003 to 2009 and WR450F models from 2003 to 2011. It uses a 12.5:1 compression ratio to deliver more power and quicker throttle response, making it a solid choice for refreshing a worn top end or gaining a competitive edge. Part number 01.2429.B confirms the exact kit.

The kit comes as a complete top-end rebuild solution, including the piston, piston rings, wrist pin, and circlips, so you can install it without sourcing additional parts.

Key specs include a standard bore of approximately 94.97 mm and a compression ratio of 12.5:1, engineered to fit the Yamaha YZ450F and WR450F platforms with high precision.

Manufactured to PROX’s exact specifications, this piston kit is built with high-quality materials and tight tolerances to ensure reliable performance under demanding riding conditions.

• Piston kit includes: piston, piston rings, wrist pin, and circlips for a complete install.
• Compatibility: Yamaha YZ450F (2003–2009) and WR450F (2003–2011) models.
• Compression ratio: 12.5:1 for enhanced power and throttle response.
• Bore size: standard bore around 94.97 mm (92.0–93.0 mm class not applicable for this kit).

Excellent economic alternative when you are looking for an OEM quality replacement piston

Mainly manufactured in Japan by reputable Original Equipment Manufacturers to ProX exact specifications and high quality standards

Sleeved cylinder piston kits are available in standard size and a Wide range of oversizes

Plated cylinder piston kits come in standard size, as well as in A, B, C and D oversizes if available

ProX leads the industry in cast and forged pistons made specifically to replace OEM parts

Comes complete with pistons, piston rings, wrist pin and circlips

The PROX Piston Kit (Part Number 01.2429.B) is designed specifically for Yamaha YZ450F models from 2003 to 2009 and WR450F models from 2003 to 2011. Crafted to deliver reliable performance and durability, this kit is ideal for rebuilding or upgrading your motorcycle's engine. The piston features a 12.5:1 compression ratio, providing enhanced power output and improved throttle response for competitive riding or recreational use. Made with high-quality materials, the kit ensures a precise fit and long-lasting performance under demanding conditions.

The kit includes all necessary components for a comprehensive rebuild, streamlining your maintenance process. Whether you're restoring your bike to peak condition or seeking a performance boost, the PROX piston kit offers excellent value and dependable quality. Its compatibility with specific Yamaha models makes it a perfect choice for enthusiasts and professional mechanics aiming for optimal engine performance and longevity.

Features:

• Designed for Yamaha YZ450F '03-'09 and WR450F '03-'11 models

• 12.5:1 compression ratio for increased power and responsiveness

• High-quality materials ensure durability and precise fit

• Complete piston kit includes all necessary components for installation

• Engineered for reliable performance in demanding conditions