The Namura NA-40019-4 Piston Kit is designed for select Yamaha YFM125G Grizzly sport utility ATVs from 2004 through 2013. This 50 mm, +1.00 oversize piston kit features a 9.0:1 compression ratio and is intended for engine rebuilds requiring an oversized replacement piston. The kit provides a dependable fit for the listed Yamaha application when the cylinder has been professionally measured and prepared for the specified piston size.
Compatible with 2004–2013 Yamaha YFM125G Grizzly models equipped with SRA suspension, this Namura piston kit is manufactured for service and replacement applications. Verify the engine, model year, bore specification, and required oversize before installation. Proper cylinder honing, piston-to-cylinder clearance, ring-gap measurement, and assembly procedures are essential for reliable performance.
Important compatibility information: This piston will not accept OEM rings, and the included or properly matched replacement rings will not work with an OEM piston. Do not mix this piston with OEM rings or use OEM rings on the Namura piston. The manufacturer part number is NA-40019-4, and the vendor part number is 187-400194. Always compare the existing engine configuration and service specifications before ordering.
Features:
- Brand: Namura
- Manufacturer Part Number: NA-40019-4
- Vendor Part Number: 187-400194
- Product Type: Piston kit
- Piston Size: 50 mm, +1.00 oversize
- Compression Ratio: 9.0:1
- Fitment: 2004–2013 Yamaha YFM125G Grizzly YFM125G models with SRA suspension
- Ring Compatibility: Will not accept OEM rings, and the supplied replacement rings will not work on an OEM piston
- Installation Requirement: Confirm cylinder measurements, bore preparation, piston clearance, and ring gap before installation
Fitment:
1989 Yamaha YFA1 Breeze 125
1990 Yamaha YFA1 Breeze 125
1991 Yamaha YFA1 Breeze 125
1992 Yamaha YFA1 Breeze 125
1993 Yamaha YFA1 Breeze 125
1994 Yamaha YFA1 Breeze 125
1995 Yamaha YFA1 Breeze 125
1996 Yamaha YFA1 Breeze 125
1997 Yamaha YFA1 Breeze 125
1998 Yamaha YFA1 Breeze 125
1999 Yamaha YFA1 Breeze 125
2000 Yamaha YFA1 Breeze 125
2001 Yamaha YFA1 Breeze 125
2002 Yamaha YFA1 Breeze 125
2003 Yamaha YFA1 Breeze 125
2004 Yamaha YFA1 Breeze 125
2004 Yamaha YFM125G Grizzly [SRA]
2005 Yamaha YFM125G Grizzly [SRA]
2005 Yamaha YFM125GH Grizzly Hunter
2006 Yamaha YFM125G Grizzly [SRA]
2006 Yamaha YFM125GH Grizzly Hunter
2007 Yamaha YFM125G Grizzly [SRA]
2007 Yamaha YFM125GH Grizzly Hunter
2008 Yamaha YFM125G Grizzly [SRA]
2008 Yamaha YFM125GH Grizzly Hunter
2009 Yamaha YFM125G Grizzly [SRA]
2010 Yamaha YFM125G Grizzly [SRA]
2011 Yamaha YFM125G Grizzly [SRA]
2012 Yamaha YFM125G Grizzly [SRA]
2013 Yamaha YFM125G Grizzly [SRA]