Namura .040 Over Bore Piston Kit for Polaris Big Boss 250 4x6 6x6 1989-1993 73mm

Namura .040 Over Bore Piston Kit for Polaris

This aftermarket .040 over bore piston kit replaces the original piston in Polaris Big Boss 250 4x6 and 6x6 ATVs from 1989 to 1993, featuring a 73mm bore diameter for reliable performance.

Overview

This Namura .040 over bore piston kit is designed for Polaris Big Boss 250 models built between 1989 and 1993. It provides a direct replacement for the factory piston, restoring compression and power. The piston kit includes a 73mm piston, rings, and wrist pin for a complete rebuild.

Built For Performance

• Precision-machined from high-strength aluminum alloy
• Includes premium steel rings for improved sealing
• Designed for .040 over bore to restore cylinder clearance
• Kit contains piston, rings, wrist pin, and circlips
• Direct fit for 73mm bore applications

Fits These Machines

• for Polaris Big Boss 250 4x6 (1989-1993)
• for Polaris Big Boss 250 6x6 (1989-1993)

On-The-Job Use

• Recreational riding on trails
• Utility work and hauling
• Engine rebuild and restoration projects

Specs At A Glance

Good To Know

Q: Does this piston kit come with rings? A: Yes, the kit includes piston rings, wrist pin, and circlips for a complete installation.

Q: Is this a direct fit for my 1991 Polaris Big Boss 250 6x6? A: This piston kit is designed for 1989-1993 Polaris Big Boss 250 models with a 73mm bore; verify your cylinder bore before ordering.

Slight variation in finish or dimensions may occur between production runs, and fit can depend on serial number, so confirm compatibility before ordering.