Namura .020 Over Bore Piston Kit for Polaris Trail Boss 250 1985-1999 72.5mm

Namura .020 Over Bore Piston Kit for Polaris

This piston kit is a .020 oversize replacement for Polaris Trail Boss 250 models from 1985 to 1999, featuring a 72.5mm bore diameter to restore engine compression and performance.

Overview

The .020 over bore piston kit for Polaris Trail Boss 250 is a precision replacement designed for engines requiring oversize pistons after cylinder boring. This 72.5mm piston kit ensures proper fitment and performance for 1985-1999 models.

Built For Performance

• Manufactured from high-silicon aluminum alloy for durability and heat resistance
• Precision ground piston skirt ensures proper cylinder wall contact
• Includes piston pin and retaining clips for complete installation
• .020 oversize (72.5mm) matches standard rebore dimension
• Designed for Polaris Trail Boss 250 engines
• Rings included for immediate use

Fits These Machines

• for Polaris Trail Boss 250 (1985-1999)

On-The-Job Use

• Restores lost compression in high-mileage Trail Boss engines
• Ideal for engine rebuilds after cylinder scoring or ring failure
• Commonly used during full top-end overhauls on Polaris ATVs
• Provides reliable power for trail riding and utility use

Specs At A Glance

Good To Know

Q: Do I need to re-use my old piston pin? A: It is recommended to use the included pin and clips for proper fit. Always follow your engine manual for assembly torque specs.

Q: Is any machining required for this oversize piston? A: Yes, the cylinder must be bored to the correct clearance for a 72.5mm piston. Have a professional machine shop perform this work.

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