The Namura NA-50070-BK1 Top End Kit is designed for select Polaris 700 engines with Nikasil-plated cylinders and a 79.96 mm piston size. This complete kit includes the piston, piston rings, wrist pin, retaining clips, top-end bearing, and gasket kit, providing the essential components for a reliable top-end rebuild. Manufacturer part number NA-50070-BK1 and vendor part number 186-5070B1.
Built for durability and consistent performance, this Namura piston uses a hypereutectic casting process that increases silicon content to help control expansion and improve wear resistance under elevated cylinder temperatures. The MOS2, or Teflon/molybdenum, coated skirts use a rolled-on application process for a strong bond, helping reduce friction, improve heat transfer, and minimize the risk of cold seizures. Machined smooth heads help reflect combustion heat and reduce carbon buildup, while anodized domes improve heat resistance and piston durability.
This top-end kit fits select Polaris applications, including the 2006-2009 Polaris Ranger 700 6X6, 2007 Polaris Ranger 700 4X4, and 2004-2007 Polaris Sportsman 700 EFI 4X4. It also fits the 2005 Polaris Sportsman 700 4X4. Confirm the vehicle year, model, cylinder specification, and required piston size before installation to ensure proper fitment. Professional installation and inspection of the cylinder, connecting rod, and related components are recommended during a top-end rebuild.
Features:
- Complete top-end kit includes piston, rings, wrist pin, retaining clips, top-end bearing, and gasket kit
- 79.96 mm piston size for compatible Nikasil-plated cylinders
- MOS2 Teflon/molybdenum-coated piston skirts help reduce friction, improve heat transfer, and minimize cold-seizure risk
- Machined smooth piston head helps reflect combustion heat and reduce carbon buildup
- Anodized piston dome improves heat resistance and durability
- Hypereutectic casting process provides controlled expansion and improved wear resistance
- Fits select 2004-2009 Polaris Ranger and Sportsman 700 models
Fitment:
2004 Polaris Sportsman 700 4x4
2004 Polaris Sportsman 700 Efi 4x4
2005 Polaris Sportsman 700 4x4
2005 Polaris Sportsman 700 Efi 4x4
2006 Polaris Ranger 700 6X6
2006 Polaris Sportsman 700 4x4
2006 Polaris Sportsman 700 Efi 4x4
2007 Polaris Ranger 700 4X4
2007 Polaris Ranger 700 6X6
2007 Polaris Sportsman 700 Efi 4x4
2008 Polaris Ranger 700 4X4
2008 Polaris Ranger 700 6X6
2009 Polaris Ranger 700 4X4
2009 Polaris Ranger 700 6X6