The Namura NA-50002-4 Piston Kit is a replacement two-stroke piston assembly designed for select Polaris 400L engines. This oversized piston measures 83.94 mm, equivalent to approximately 3.305 inches, and features an 11:1 compression ratio for dependable performance in properly rebuilt applications. The kit is intended for use with a compatible oversized cylinder bore and is engineered to replace a worn or damaged piston during an engine rebuild.
This Namura piston kit is compatible with the 1994–1999 Polaris Sport 400L, 1997 Polaris Sportsman 400L 4x4, 1996–1997 Polaris Xpress 400L, and 1994 Polaris 400L 2X4, subject to cylinder and engine configuration. Confirm the original piston specification, bore size, compression ratio, and model application before installation. The NA-50002-4 is not compatible with OEM piston rings, and its rings will not work on an OEM piston; use the rings supplied or specified for this Namura piston kit.
Manufactured by Namura, this replacement piston kit is designed to support reliable service when installed with correct clearances, lubrication, and engine-rebuild procedures. Professional installation is recommended, including cylinder inspection, measurement, honing or boring as required, and verification of ring end gap before assembly. Vendor part number NA-50002-4 and manufacturer part number NA-50002-4 identify this application-specific piston kit.
Features:
- Size: 83.94 mm, approximately 3.305 inches, with a +1.00 mm oversize specification
- Model: Two-stroke piston kit with an 11:1 compression ratio
- Brand: Namura
- Manufacturer Part Number: NA-50002-4
- Vendor Part Number: NA-50002-4
- Fitment: 1994–1999 Polaris Sport 400L
- Fitment: 1997 Polaris Sportsman 400L 4x4
- Fitment: 1996–1997 Polaris Xpress 400L
- Fitment: 1994 Polaris 400L 2X4
- Compatibility: Will not accept OEM rings, and the supplied rings are not compatible with an OEM piston
- Installation: Verify cylinder bore, piston clearance, ring end gap, and engine configuration before installation
Fitment:
1994 Polaris 400L 2X4
1994 Polaris 400L 4X4
1994 Polaris Sport 400L
1995 Polaris 400L 2X4
1995 Polaris Scrambler 400 4X4
1995 Polaris Sport 400L
1995 Polaris Xplorer 400 4X4
1996 Polaris Scrambler 400 4X4
1996 Polaris Sport 400L
1996 Polaris Xplorer 400 4X4
1996 Polaris Xpress 400L
1997 Polaris Scrambler 400 4X4
1997 Polaris Sport 400L
1997 Polaris Sportsman 400L 4x4
1997 Polaris Xplorer 400 4X4
1997 Polaris Xpress 400L
1998 Polaris Scrambler 400 4X4
1998 Polaris Sport 400L
1998 Polaris Xplorer 400 4X4
1999 Polaris Scrambler 400 2X4
1999 Polaris Scrambler 400 4X4
1999 Polaris Sport 400L
1999 Polaris Xplorer 400 4X4
2000 Polaris Scrambler 400 2X4
2000 Polaris Scrambler 400 4X4
2000 Polaris Xplorer 400 4X4
2001 Polaris Scrambler 400 2X4
2001 Polaris Scrambler 400 4X4
2001 Polaris Xplorer 400 4X4
2002 Polaris Scrambler 400 2X4
2002 Polaris Scrambler 400 4X4
2002 Polaris Xplorer 400L
2003 Polaris Trail Blazer 400