The Namura NA-40012-BK Top End Kit is designed for select Yamaha YFM700 ATV applications, including the Grizzly Fi 4WD with IRS and the YFM700R Raptor. This 101.98 mm replacement kit is engineered for reliable top-end service and includes the essential components needed to refresh the piston assembly and cylinder head sealing surfaces. The kit includes a piston, piston rings, wrist pin, wrist-pin clips, top-end bearing, and gasket kit.
Designed for durability and consistent performance, the piston features MOS2, or Teflon/molybdenum, coated skirts. The rolled-on coating process creates a strong bond that helps reduce friction, improve heat transfer, and minimize the risk of cold seizures. Machined smooth heads help reflect combustion heat and reduce carbon buildup, while the anodized dome improves heat resistance and durability. The hypereutectic casting process adds silicon for reduced expansion, improved wear resistance, and dependable operation at elevated cylinder temperatures.
This Namura top end kit has a 9.2:1 compression ratio and is intended for compatible Yamaha engines using the specified 101.98 mm piston size. Fitment includes the 2007–2013 Yamaha YFM700G Grizzly Fi 4WD with IRS and the 2006–2008 Yamaha YFM700R Raptor. Verify the year, model, engine configuration, and required piston size before installation. The manufacturer part number is NA-40012-BK, and the vendor part number is 186-4012B.
Features:
- Complete top-end kit includes piston, rings, wrist pin, clips, top-end bearing, and gasket kit
- 101.98 mm piston size with a 9.2:1 compression ratio for select Yamaha YFM700 applications
- MOS2 Teflon/molybdenum-coated piston skirts help reduce friction, improve heat transfer, and minimize cold-seizure risk
- Machined smooth piston heads help reflect combustion heat and reduce carbon buildup
- Anodized piston domes provide increased heat resistance and durability
- Hypereutectic casting process provides reduced expansion and improved wear resistance
- Fits 2007–2013 Yamaha YFM700G Grizzly Fi 4WD with IRS
- Fits 2006–2008 Yamaha YFM700R Raptor
- Brand: Namura
- Manufacturer part number: NA-40012-BK
- Vendor part number: 186-4012B
Fitment:
2006 Yamaha YFM700R Raptor
2007 Yamaha YFM700G Grizzly Fi 4WD [IRS]
2007 Yamaha YFM700R Raptor
2008 Yamaha YFM700G Grizzly Fi 4WD [IRS]
2008 Yamaha YFM700R Raptor
2008 Yamaha YXR700F Rhino 700
2009 Yamaha YFM700G Grizzly Fi 4WD [IRS]
2009 Yamaha YFM700R Raptor
2009 Yamaha YXR700F Rhino 700
2010 Yamaha YFM700G Grizzly Fi 4WD [IRS]
2010 Yamaha YFM700R Raptor
2011 Yamaha YFM700G Grizzly Fi 4WD [IRS]
2011 Yamaha YFM700R Raptor
2011 Yamaha YXR700F Rhino 700
2012 Yamaha YFM700G Grizzly Fi 4WD [IRS]
2012 Yamaha YFM700R Raptor
2012 Yamaha YXR700F Rhino 700
2013 Yamaha YFM700G Grizzly Fi 4WD [IRS]
2013 Yamaha YFM700R Raptor
2013 Yamaha YXR700F Rhino 700
2014 Yamaha YFM700R Raptor
2015 Yamaha YFM700R Raptor
2016 Yamaha YFM700R Raptor