Namura .020 Over Bore Piston Kit fits Polaris 850 Scrambler & Sportsman 87.5mm

Namura .020 Over Bore Piston Kit for Polaris

This Namura .020 oversize piston kit fits Polaris 850 Scrambler and Sportsman models, providing a reliable 87.5mm bore replacement for worn or damaged factory pistons after an overbore.

Overview

The Namura .020 over bore piston kit is a direct-fit replacement for Polaris 850 engines found in Scrambler and Sportsman ATVs, delivering consistent compression and power. This piston kit uses a 87.5mm bore size to restore engine performance after cylinder machining, making it a trusted option for rebuilding high-mileage or overheated motors.

Built For Performance

• Precision-machined 87.5mm piston with .020 oversize
• High-silicone aluminum alloy reduces expansion and scuffing
• Moly-coated skirt for reduced friction and quicker break-in
• Includes rings, wrist pin, and circlips for complete installation
• Manufactured to meet or exceed OEM specifications

Fits These Machines

• for Polaris Scrambler 850
• for Polaris Sportsman 850

On-The-Job Use

• Engine rebuilding after top-end failure
• Restoring compression in worn 850 engines
• Cylinder overbore to remove scoring or taper
• Performance rebuilds requiring a fresh piston set

Specs At A Glance

Good To Know

Q: Can I install this piston without machining the cylinder? A: No, a .020 over bore requires the cylinder to be professionally honed or bored to 87.5mm for proper clearance.

Q: Does this kit work in a Polaris 850 RZR? A: This kit is designed for Scrambler and Sportsman models; confirm with your engine serial number for compatibility with other Polaris 850 applications.

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