SPI .040 Over Bore Piston Kit for Polaris 500 RMK fits 1997 1998 1999 73mm

SPI .040 Over Bore Piston Kit for Polaris 500 RMK

This SPI .040 over bore piston kit replaces the original piston in Polaris 500 RMK snowmobiles with a 73mm bore, restoring compression and performance after a top end rebuild.

Overview

The SPI .040 over bore piston kit is designed for Polaris 500 RMK models from 1997 to 1999, providing a high-quality replacement that brings the engine back to life. Featuring a 73mm bore size, this piston kit is a direct fit for the 500cc engine, ensuring reliable operation on the mountain.

Built For Performance

• Precision machined 73mm piston with .040 oversize
• High-strength aluminum alloy construction for durability
• Includes piston rings and wrist pin for complete installation
• Engineered to match OEM specifications for reliable fitment
• Tested for consistent compression and smooth operation

Fits These Machines

• for Polaris 500 RMK (1997-1999)

On-The-Job Use

• Commonly used during top-end rebuilds on Polaris mountain snowmobiles
• Ideal for restoring power in high-mileage RMK engines
• Suitable for deep snow and backcountry riding

Specs At A Glance

Good To Know

Q: Do I need to replace the cylinder as well? A: Typically, a .040 over bore piston matches a freshly honed cylinder; if the cylinder is worn beyond spec, boring may be required.

Q: What other parts should I replace with this piston? A: It is recommended to install a new gasket set and check the wrist pin bearing for wear during a top-end rebuild.

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