The Namura FX-40045-B Forged Piston Kit is designed for reliable replacement performance in select Yamaha four-stroke off-road motorcycles. This high-compression piston kit features a 94.96 mm piston size and a 12.5:1 compression ratio, making it a suitable choice for engine rebuilds, top-end service, and performance-focused maintenance.
Each Namura piston kit includes an individually wrapped forged piston, OEM-quality piston rings in a separate protective box, an OEM-quality wrist pin, and cir-clips. The included components are matched to support proper installation and dependable operation when used with compatible engine components and according to the manufacturer’s service procedures.
Fitment: The Namura FX-40045-B fits 2003–2009 Yamaha YZ450F models and 2003–2005 Yamaha WR450F models. Confirm year, engine specifications, piston clearance, and compression requirements before installation. Manufacturer part number: FX-40045-B. Vendor part number: 184-F40045B.
Features:
- Forged piston: Provides a durable replacement component for compatible Yamaha four-stroke engines.
- 94.96 mm piston size: Designed for the specified Yamaha YZ450F and WR450F applications.
- 12.5:1 compression ratio: Supports the original performance configuration for compatible engines.
- OEM-quality piston rings: Included as a matched ring set and packed separately for protection.
- OEM-quality wrist pin and cir-clips: Provides the essential hardware required for piston installation.
- Fitment: Fits 2003–2009 Yamaha YZ450F and 2003–2005 Yamaha WR450F models.
Fitment:
2003 Yamaha WR450F
2003 Yamaha YZ450F
2004 Yamaha WR450F
2004 Yamaha YZ450F
2005 Yamaha WR450F
2005 Yamaha YZ450F
2006 Yamaha WR450F
2006 Yamaha YZ450F
2007 Yamaha WR450F
2007 Yamaha YZ450F
2008 Yamaha WR450F
2008 Yamaha YZ450F
2009 Yamaha WR450F
2009 Yamaha YZ450F
2010 Yamaha WR450F
2011 Yamaha WR450F
2012 Yamaha WR450F
2013 Gas-Gas EC 450F
2013 Yamaha WR450F
2014 Gas-Gas EC 450F
2014 Yamaha WR450F
2015 Gas-Gas EC 450F
2015 Yamaha WR450F