SPI .020 Over Bore Piston Kit for Polaris XC 500, XC SP 500 RMK Classic 71mm

SPI .020 Over Bore Piston Kit for Polaris

This SPI .020 Over Bore Piston Kit is an aftermarket replacement for Polaris XC 500, XC SP 500, and RMK Classic snowmobiles, featuring a 71mm bore size to restore compression and performance.

Overview

This SPI .020 Over Bore Piston Kit provides a direct‑fit replacement piston for Polaris two‑stroke snowmobile engines. The 71mm bore and .020 over sizing compensate for cylinder wear, delivering fresh ring seal and restored power output for models like the XC 500 and RMK Classic.

Built For Performance

• High‑strength cast piston with reinforced skirt for durability
• Includes premium piston rings, wrist pin, and circlips
• Precision‑machined to exact OEM dimensions for easy installation
• Lightweight design reduces reciprocating mass for snappier throttle response
• Compatible with standard fuel and oil mixtures

Fits These Machines

• for Polaris XC 500
• for Polaris XC SP 500
• for Polaris RMK Classic

On-The-Job Use

• Snowmobile trail riding and cross‑country touring
• Mountain and deep‑snow riding
• Performance recreation and ice racing
• Engine rebuilds and top‑end overhauls

Specs At A Glance

Good To Know

Q: Do I need to hone the cylinder before installing this piston? A: Yes, a fresh cylinder hone is essential to ensure proper ring seating and crosshatch for oil retention.

Q: Can this kit be used with aftermarket cylinder porting? A: It may be used with mild porting, but always verify piston‑to‑wall clearance and ring end gap before final assembly.

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