The Namura NA-50000-2 Piston Kit is designed for select Polaris 250 ATV applications, including the 1991–1992 Polaris Big Boss 250 6X6 and 1988–1993 Polaris Trail Boss 250 2X4, along with the 1989–1990 Polaris Trail Boss 250 4X4. This oversize piston kit measures 72.46 mm, or +0.50 mm over the standard piston size, making it suitable for compatible engines machined to the required oversize specification.
Manufacturer part number NA-50000-2 and vendor part number NA-50000-2 identify this Namura replacement piston kit. It is intended for engine rebuilding and replacement applications where the cylinder has been properly inspected and prepared for the +0.50 mm piston size. Verify the engine model, bore specification, and service requirements before installation to ensure correct fitment.
Important: This kit will not accept OEM piston rings, and the included rings will not work with an OEM piston. Use the correct rings supplied or specified for the Namura piston and confirm all piston, ring, cylinder, and clearance specifications during assembly. Professional installation is recommended for proper performance and durability.
Features:
- Brand: Namura
- Manufacturer part number: NA-50000-2
- Vendor part number: NA-50000-2
- Piston size: 72.46 mm / +0.50 mm oversize
- Application: Select Polaris 250 ATV engines
- Fitment: 1991–1992 Polaris Big Boss 250 6X6
- Fitment: 1988–1993 Polaris Trail Boss 250 2X4
- Fitment: 1989–1990 Polaris Trail Boss 250 4X4
- Compatibility: Will not accept OEM piston rings, and the included rings will not work with an OEM piston
Fitment:
1985 Polaris Trail Boss 250 2X4
1986 Polaris Trail Boss 250 2X4
1987 Polaris Trail Boss 250 2X4
1987 Polaris Trail Boss 250 4X4
1988 Polaris Trail Boss 250 2X4
1988 Polaris Trail Boss 250 4X4
1988 Polaris Trail Boss 250R/Es
1989 Polaris Big Boss 250 4X6
1989 Polaris Trail Boss 250 2X4
1989 Polaris Trail Boss 250 4X4
1990 Polaris Big Boss 250 4X6
1990 Polaris Trail Blazer 250
1990 Polaris Trail Boss 250 2X4
1990 Polaris Trail Boss 250 4X4
1991 Polaris Big Boss 250 4X6
1991 Polaris Big Boss 250 6X6
1991 Polaris Trail Blazer 250
1991 Polaris Trail Boss 250 2X4
1991 Polaris Trail Boss 250 4X4
1992 Polaris Big Boss 250 4X6
1992 Polaris Big Boss 250 6X6
1992 Polaris Trail Blazer 250
1992 Polaris Trail Boss 250 2X4
1992 Polaris Trail Boss 250 4X4
1993 Polaris Trail Blazer 250
1993 Polaris Trail Boss 250 2X4
1993 Polaris Trail Boss 250 4X4
1994 Polaris Trail Blazer 250
1994 Polaris Trail Boss 250 2X4
1995 Polaris Trail Blazer 250
1995 Polaris Trail Boss 250 2X4
1996 Polaris Trail Blazer 250
1996 Polaris Trail Boss 250 2X4
1997 Polaris Trail Blazer 250
1997 Polaris Trail Boss 250 2X4
1998 Polaris Trail Blazer 250
1998 Polaris Trail Boss 250 2X4
1999 Polaris Trail Blazer 250
1999 Polaris Trail Boss 250 2X4
2000 Polaris Trail Blazer 250
2000 Polaris Xplorer 250 4X4
2001 Polaris Trail Blazer 250
2001 Polaris Xplorer 250 4X4
2002 Polaris Trail Blazer 250
2002 Polaris Xplorer 250 4X4
2003 Polaris Trail Blazer 250
2004 Polaris Trail Blazer 250
2005 Polaris Trail Blazer 250
2006 Polaris Trail Blazer 250