The NAMURA NA-50080-BK Top End Kit is a complete replacement solution for selected Polaris 800 power sports applications. The kit includes a piston, piston rings, wrist pin, retaining clips, top-end bearing, and gasket kit, providing the primary components needed for a reliable top-end rebuild. The 79.96 mm piston is engineered for the specified Polaris engine applications and features an 11:1 compression ratio.
The piston uses a hypereutectic casting process with increased silicon content to help control expansion, improve wear resistance, and withstand elevated cylinder temperatures. Its MOS2, or Teflon/molybdenum, coated skirts use a rolled-on application process designed to create a stronger bond than conventional spray-on coatings. This coating helps reduce friction, improve heat transfer, and minimize the risk of cold seizure during operation.
Additional piston features include machined smooth heads to help reflect combustion heat and reduce carbon buildup, along with anodized domes for improved heat resistance and durability. These design elements help protect the piston in demanding riding and utility conditions. Manufacturer part number NA-50080-BK and vendor part number 186-5080B identify this NAMURA replacement top-end kit.
Fitment: Fits 2008 Polaris RZR 800, 2009 Polaris RZR 800, 2010 Polaris RZR 800, 2010 Polaris RZR 800 S, 2010 Polaris Ranger Crew 800 4x4, 2009 Polaris Sportsman Big Boss 6x6 800, 2010 Polaris Sportsman Big Boss 6x6 800, 2008 Polaris Sportsman Touring 800, 2009 Polaris Sportsman Touring 800, and 2007 Polaris Sportsman X2 800 EFI. Verify the model year and engine specifications before installation.
Features:
- Complete top-end kit includes piston, rings, wrist pin, retaining clips, top-end bearing, and gasket kit
- 79.96 mm piston with an 11:1 compression ratio for specified Polaris 800 applications
- MOS2 Teflon/molybdenum coated 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 domes improve heat resistance and piston durability
- Hypereutectic casting process provides controlled expansion, increased wear resistance, and improved high-temperature performance
- Brand: NAMURA
- Manufacturer part number: NA-50080-BK
- Vendor part number: 186-5080B
Fitment:
2005 Polaris Sportsman 800 EFI
2006 Polaris Sportsman 800 EFI
2007 Polaris Sportsman 800 EFI
2007 Polaris Sportsman X2 800 EFI
2008 Polaris RZR 800
2008 Polaris Sportsman Touring 800
2008 Polaris Sportsman X2 800 EFI
2009 Polaris RZR 800
2009 Polaris Sportsman Big Boss 6X6 800
2009 Polaris Sportsman Touring 800
2009 Polaris Sportsman X2 800 EFI
2010 Polaris Ranger 800 4x4
2010 Polaris Ranger 800 6X6
2010 Polaris Ranger Crew 800 4x4
2010 Polaris RZR 800
2010 Polaris RZR 800 S
2010 Polaris Sportsman 800 EFI
2010 Polaris Sportsman Big Boss 6X6 800