Namura NA-50090K Top End Kit for Polaris RZR XP 900, 92.95 mm Standard Bore, 10.6:1 Compression

The Namura NA-50090K Top End Kit is designed for twin-cylinder Polaris RZR XP 900 engines requiring a 92.95 mm standard-bore piston setup with a 10.6:1 compression ratio. This complete kit includes the piston, piston rings, wrist pin, retaining clips, top-end bearing, and gasket kit for a comprehensive top-end rebuild. It is engineered for direct fitment on 2011 and 2012 Polaris RZR XP 900 and RZR XP 900 LE models.

Namura manufactures this piston using a hypereutectic casting process that increases silicon content for controlled expansion, added wear resistance, and improved durability under elevated cylinder temperatures. The piston skirts feature a MOS2 coating made from Teflon and molybdenum. Its rolled-on application creates a stronger bond than conventional spray-on coatings while helping reduce friction, improve heat transfer, and minimize the risk of cold seizures during operation.

The machined smooth piston heads help reflect combustion heat and reduce carbon buildup, supporting protection of the piston crown and consistent engine performance. Anodized domes add heat resistance and durability, with increased strength compared with non-anodized piston designs. The Namura NA-50090K kit is a practical replacement solution for restoring compression and renewing critical top-end components while maintaining the original engine fitment requirements.

Features:

• Complete Top End Kit: Includes piston, rings, wrist pin, retaining clips, top-end bearing, and gasket kit.
• Vehicle Fitment: Fits 2011 and 2012 Polaris RZR XP 900 and RZR XP 900 LE models.
• Standard Bore: Uses a 92.95 mm standard-bore piston for compatible Polaris twin-cylinder engines.
• Compression Ratio: Designed for a 10.6:1 compression ratio.
• MOS2-Coated Skirts: Rolled-on Teflon and molybdenum coating helps reduce friction, improve heat transfer, and minimize cold-seizure risk.
• Machined Smooth Heads: Reflect combustion heat and help reduce carbon buildup for improved piston protection.
• Anodized Domes: Improve heat resistance and durability compared with non-anodized piston domes.
• Hypereutectic Casting: Provides controlled expansion, increased wear resistance, and improved performance at higher cylinder temperatures.
• Brand and Part Number: Namura manufacturer part number NA-50090K.