Namura Top-End Repair Kit NA-40010-4K fits 2002-2004 Yamaha Grizzly 660 YFM660F 4X4 / 2004-2007 Yamaha RHINO 660 YXR660FA 4X4 / 2005-2006 Yamaha Grizzly 660 YFM660FA 4X4 / 2006 Yamaha RHINO 660 YXR660FASE 4X4 Special Edition

Namura piston kits come with the piston individually wrapped; a set of OEM quality rings packed in their own box, a wrist pin, and circlips. MOS2 (Teflon/Molybdenum) Coated Skirts: A rolled-on application process provides a bond that is 10 times stronger than other spray on coatings. Benefits include increased heat transfer, reduced friction, and helping to eliminate cold seizures. Machined Smooth Heads: Reflects combustion heat and reduces carbon buildup, protecting the top of the piston. Some tests have shown this feature can increase horsepower and fuel economy by up to 6%. Anodized Domes: Increases heat resistance and durability; pistons with anodized domes are 75% stronger than non-anodized pistons. Hypereutectic Casting Process: Provides higher silicon content for reduced expansion rates and additional wear resistance; it also has an ability to withstand higher cylinder temperatures. Namura gaskets are manufactured to OE-specs, which means no trimming or fitment issues. Our materials are explicitly selected for their temperature, oil, fuel, and coolant-resistant qualities as well as tested using ASTM standards. Each design is evaluated against rigid quality-control standards to ensure each set meets or exceeds OE performance.