The NAMURA NA-50091-BK Top End Kit is a complete replacement solution for select Polaris 900 twin-cylinder engines. This kit includes a piston, piston rings, wrist pin, wrist-pin clips, top-end bearing, and gasket kit, providing the essential components needed for a top-end rebuild. The kit is designed for a 92.96 mm piston bore with a +0.01 oversize specification and supports dependable fitment across compatible Polaris RZR and Ranger applications.
The NAMURA hypereutectic piston is manufactured with increased silicon content to help reduce thermal expansion and improve wear resistance. Its design is engineered to withstand elevated cylinder temperatures while maintaining reliable performance. MOS2, or Teflon and molybdenum, coated piston skirts use a rolled-on application process that creates a durable bond and helps reduce friction, improve heat transfer, and minimize the risk of cold seizures during operation.
The piston also features machined smooth heads to reflect combustion heat, help reduce carbon buildup, and protect the piston crown. Anodized domes provide increased heat resistance and durability, with greater strength than non-anodized piston domes. The NAMURA NA-50091-BK fits 2015–2016 Polaris RZR 900, 2015–2016 Polaris RZR 900 S, 2016 Polaris RZR 900 Trail, and 2013–2017 Polaris Ranger XP 900 models. Verify the vehicle model, year, bore specification, and engine configuration before installation.
Features:
- Complete top-end kit includes piston, rings, wrist pin, clips, top-end bearing, and gasket kit
- MOS2-coated piston skirts help reduce friction, improve heat transfer, and reduce the risk of cold seizures
- 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, improved wear resistance, and high-temperature durability
- 92.96 mm bore with +0.01 oversize specification
- Fits select 2013–2017 Polaris RZR 900 and Ranger XP 900 twin-cylinder applications
Fitment:
2013 Polaris Ranger XP 900
2014 Polaris Ranger XP 900
2015 Polaris Ranger XP 900
2015 Polaris RZR 900
2015 Polaris RZR 900 S
2016 Polaris Ranger XP 900
2016 Polaris RZR 900
2016 Polaris RZR 900 S
2016 Polaris RZR 900 Trail
2017 Polaris Ranger Crew XP 1000
2017 Polaris Ranger Crew XP 900
2017 Polaris Ranger XP 900
2017 Polaris RZR 900
2017 Polaris RZR 900 S
2018 Polaris Ranger Crew XP 900
2018 Polaris Ranger XP 900
2018 Polaris RZR 1000 RS1
2018 Polaris RZR 900
2018 Polaris RZR 900 S