The NAMURA NA-40008 Piston Kit is a standard-bore replacement piston assembly designed for select Yamaha 400 ATV applications. With an 84.42 mm piston size and a 10.5:1 compression ratio, this kit supports dependable engine rebuilding and restoration for compatible Yamaha Kodiak and Grizzly models. It is manufactured by NAMURA and identified by manufacturer part number NA-40008 and vendor part number NA-40008.
This piston kit fits the 2000–2006 Yamaha YFM400FA Kodiak 4WD with SRA, the 2003 Yamaha YFM400A Kodiak 2WD with SRA, and the 2007–2008 Yamaha YFM400FG Grizzly 4WD with IRS. Verify the exact model, year, drivetrain configuration, bore specification, and compression requirements before installation to ensure proper fitment.
Important: The NAMURA NA-40008 piston is not compatible with OEM piston rings, and OEM piston rings will not work with this piston. Use the correct compatible ring set and installation components specified for the NAMURA piston. Professional installation and proper engine clearances are recommended for reliable operation and long service life.
Features:
- Standard-bore 84.42 mm piston size
- 10.5:1 compression ratio
- Designed for select Yamaha Kodiak and Grizzly 400 ATV models
- Compatible with 2000–2006 Yamaha YFM400FA Kodiak 4WD models with SRA
- Compatible with the 2003 Yamaha YFM400A Kodiak 2WD with SRA
- Compatible with 2007–2008 Yamaha YFM400FG Grizzly 4WD models with IRS
- NAMURA manufacturer part number: NA-40008
- OEM piston rings are not compatible; use the correct NAMURA-compatible ring set
Fitment:
2000 Yamaha YFM400A Kodiak 2WD [SRA]
2000 Yamaha YFM400FA Kodiak 4WD [SRA]
2001 Yamaha YFM400A Kodiak 2WD [SRA]
2001 Yamaha YFM400FA Kodiak 4WD [SRA]
2002 Yamaha YFM400A Kodiak 2WD [SRA]
2002 Yamaha YFM400FA Kodiak 4WD [SRA]
2003 Yamaha YFM400A Kodiak 2WD [SRA]
2003 Yamaha YFM400FA Kodiak 4WD [SRA]
2004 Yamaha YFM400A Kodiak 2WD [SRA]
2004 Yamaha YFM400FA Kodiak 4WD [SRA]
2005 Yamaha YFM400FA Kodiak 4WD [SRA]
2006 Yamaha YFM400FA Kodiak 4WD [SRA]
2007 Yamaha YFM400FG Grizzly 4WD [IRS]
2008 Yamaha YFM400FG Grizzly 4WD [IRS]