Namura .020 Over Bore Piston Kit for Yamaha YZ250 & YZ250X fits 1999-2024 66.9mm

.020 Over Bore Piston Kit for Yamaha

This .020 over bore piston kit fits Yamaha YZ250 and YZ250X two-stroke models from 1999 to 2024, providing a high-quality replacement piston with a 66.9mm bore size for engine rebuilds or oversize bore applications.

Overview

This .020 over bore piston kit is designed for Yamaha YZ250 and YZ250X motorcycles manufactured between 1999 and 2024. It offers a durable piston ring set and wrist pin for a reliable top end rebuild, ensuring consistent power delivery and compression in your two-stroke engine.

Built For Performance

• Precision-machined from high-strength aluminum alloy
• Includes piston rings, wrist pin, and circlips
• .020 inch oversize for worn cylinder bores
• Designed for high-revving two-stroke applications
• Tested for durability and heat resistance

Fits These Machines

• for Yamaha YZ250 (1999-2024)
• for Yamaha YZ250X (1999-2024)

On-The-Job Use

• Motocross and supercross racing
• Enduro and cross-country competition
• Trail riding and off-road use

Specs At A Glance

Good To Know

Q: Do I need to hone the cylinder before installing this piston? A: Yes, when installing an oversize piston the cylinder should be properly honed or bored to match the new piston for correct clearance and ring seating.

Q: Does this kit include a gasket set? A: This is a piston kit only and does not include gaskets; a separate top end gasket kit is recommended for a complete rebuild.

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