Upgrade your Harley-Davidson engine performance with Keith Black Pistons hypereutectic dome top pistons. Engineered specifically for Evolution Big Twin models, these pistons are manufactured from a high-silicon hypereutectic aluminum alloy designed to withstand the high thermal demands of air-cooled engines while maintaining minimal thermal expansion.

This low expansion rate allows for tighter piston-to-cylinder operating clearances, ensuring superior ring seal, reduced noise, and extended service life. Delivering a 9.6:1 compression ratio with standard 80cc combustion chambers, this complete kit includes pistons, rings, wrist pins, and clips for a full engine refresh.

Key Features

Highlights

• Engineered from cast 16% silicon hypereutectic alloy ideal for air-cooled environments.
• Low thermal expansion rate allows for tighter piston-to-cylinder operating clearances.
• Yields a 9.6:1 compression ratio with 80cc cylinder heads.
• Includes all necessary components for installation: pistons, rings, wrist pins, and clips.

Compatibility

Compatible with 1984–1999 Harley-Davidson Big Twin motorcycles equipped with Evolution (Evo) engines requiring a +.040 in. oversize bore (89.9 mm / 3.538 in.).

What's included

• 2 x Keith Black Hypereutectic Pistons
• 1 x Complete Piston Ring Set
• 2 x Wrist Pins
• 1 x Set of Wrist Pin Clips

Downloads

• Download Product information ( PDF)