SPI .020 Over Bore Piston Kit for Polaris 550 Fan Cooled 1999-2021 - 73.5mm

SPI .020 Over Bore Piston Kit for Polaris 550 Fan Cooled

This SPI .020 over bore piston kit is a direct replacement for Polaris 550 fan cooled engines from 1999-2021. The 73.5mm piston kit includes rings and wrist pin for a complete top-end rebuild.

Overview

Designed for Polaris 550 fan cooled snowmobile and ATV engines, this SPI .020 over bore piston kit brings the bore to 73.5mm to restore compression and power. The kit contains a cast piston, piston rings, and wrist pin, making it a convenient solution for engine rebuilds.

Built For Performance

• Cast aluminum piston with precision-machined ring grooves
• Includes high-quality piston rings for proper sealing
• Wrist pin and circlips included for complete installation
• 0.020 inch overbore provides a clean cylinder surface
• Match-ported to factory specifications for reliable operation

Fits These Machines

• for Polaris 550 fan cooled engines (1999-2021)
• for Polaris snowmobiles with 550 fan cooled engine
• for Polaris ATVs with 550 fan cooled engine

On-The-Job Use

• Engine rebuilds after cylinder wear or piston damage
• Performance restoration for older Polaris 550 fan cooled engines
• Top-end overhaul during seasonal maintenance

Specs At A Glance

Good To Know

Q: Do I need to hone the cylinder before installing this piston kit? A: Yes, the cylinder should be professionally honed to the correct 73.5mm bore size to ensure proper ring seating and compression.

Q: Can I use this piston kit in a Polaris 550 liquid cooled engine? A: No, this kit is specifically designed for the fan cooled version only, so confirm your engine type before purchasing.

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