Namura .040 Over Bore Piston Kit for Yamaha YFZ50 fits 2017-2026 40mm

.040 Over Bore Piston Kit for Yamaha YFZ50

This .040 over bore piston kit for Yamaha YFZ50 includes a 40mm piston, rings, and wrist pin, designed to restore engine performance in 2017-2026 models.

Overview

This .040 over bore piston kit for Yamaha YFZ50 is a 40mm diameter piston assembly intended for use when cylinder wear requires oversizing. It fits Yamaha YFZ50 models from 2017 to 2026, providing a direct replacement that restores compression and power. The kit includes the piston, rings, and wrist pin for a complete installation.

Built For Performance

• Oversized .040 inches (40mm) to accommodate worn cylinders
• Includes piston, rings, and wrist pin
• Manufactured from high-strength aluminum alloy
• Precision-machined for accurate fit and minimal friction
• Rings are designed for optimal sealing and oil control

Fits These Machines

• for Yamaha YFZ50 (2017-2026)

On-The-Job Use

• Used during engine rebuilding when the cylinder requires overboring
• Ideal for restoring lost compression and power in high-hour YFZ50 ATVs
• Suitable for both recreational and competitive use

Specs At A Glance

Good To Know

Q: Do I need to replace the cylinder when using this over bore piston? A: The cylinder must be professionally bored to 40mm to match this piston; honing is also recommended for proper ring seating.

Q: Can this piston kit be used on other Yamaha models? A: This kit is designed specifically for Yamaha YFZ50 engines; it will not fit other models without modification.

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