The Namura NA-50003-2K Top End Kit is designed for select Polaris 300 two-stroke engines and includes the essential components needed for a reliable top-end rebuild. The kit contains a piston, piston rings, wrist pin, wrist-pin clips, top-end bearing, and gasket kit. It is engineered for a 74.97 mm standard-size piston application with a 0.50 mm oversize configuration, supporting proper fitment and dependable engine performance when used with the correct cylinder specifications.
Namura uses a hypereutectic casting process to increase silicon content, helping reduce expansion rates and improve wear resistance under elevated cylinder temperatures. The piston features MOS2, or Teflon and molybdenum, coated skirts applied through a rolled-on process for strong adhesion. This coating helps improve heat transfer, reduce friction, and minimize the risk of cold seizures during engine operation.
The machined smooth piston head helps reflect combustion heat and reduce carbon buildup, while the anodized dome improves heat resistance and durability. Together, these features help protect the piston in demanding riding conditions. This Namura top-end kit fits the 1996–1999 Polaris Xpress 300 and 1996–1999 Polaris Xplorer 300 4X4. Confirm the cylinder bore, engine specifications, and required oversize before installation.
Manufacturer: Namura
Vendor Part Number: NA-50003-2K
Application: Two-stroke Polaris 300 engines
Features:
- Complete top-end kit includes piston, rings, wrist pin, clips, top-end bearing, and gasket kit
- 74.97 mm standard-size piston with a 0.50 mm oversize configuration
- MOS2-coated piston skirts help reduce friction, improve heat transfer, and help prevent cold seizures
- Machined smooth piston head helps reflect combustion heat and reduce carbon buildup
- Anodized piston dome increases heat resistance and durability
- Hypereutectic casting process provides reduced expansion rates and improved wear resistance
- Fits 1996–1999 Polaris Xpress 300 models
- Fits 1996–1999 Polaris Xplorer 300 4X4 models
Fitment:
1996 Polaris Xplorer 300 4X4
1996 Polaris Xpress 300
1997 Polaris Xplorer 300 4X4
1997 Polaris Xpress 300
1998 Polaris Xplorer 300 4X4
1998 Polaris Xpress 300
1999 Polaris Xplorer 300 4X4
1999 Polaris Xpress 300