Keith Black pistons kit, flat top 8.5:1 compression standard bore for Harley Davidson Big Twin Evolution 80ci 1340cc. Evolution is the key word as these Keith Black Performance Piston Kits were spawned from this successful manufacturer’s line of automotive pistons.
Lightweight permanent mold cast pistons are manufactured from Hypereutectic 390 Alloy, contain 16-18% silicon, and are heat treated to T-6 specifications producing a stronger than stock piston. This special alloy keeps heat confined to the combustion chamber and reduces heat transfer to the piston itself. The result is a cooler running piston that can be fitted with a clearance as small as .00075 inch. Piston expansion is reduced by as much as 20% over conventional pistons. These tighter fitting pistons rock less, support the rings better, are more durable and retain compression better for maximum power.
The key feature to these pistons is the accumulator groove between the top and second ring. This groove between the rings tends to average the normal pressure between the first and second ring, keeping the pressure low enough to prevent lifting of the top ring while maintaining preload on the second, oil scraping, ring.
- Keith Black pistons kit 8.5:1 compression 3.498 inch standard bore, Standard stroke
- Includes 2 Flat Top pistons, wrist pins, spiral locks, engine assembly lube, and Hastings Moly rings.
- Cast pistons are manufactured from Hypereutectic 390 Alloy, contain 16-18% silicon
- Reduces heat transfer to the piston itself
- Clearance as small as .00075 inch
- Expansion is reduced by as much as 20%
- Accumulator groove between the top and second ring.
- For Harley Davidson Big Twin Evolution 80ci 1340cc