Keith Black Pistons Flat Top Pistons KB258.005 for Big Twin 1984-1999
$566.15
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Keith Black Pistons Flat Top Pistons KB258.005 for Big Twin 1984-1999
$566.15
Engineered for high performance and durability, these Keith Black Pistons flat top pistons are cast from hypereutectic alloy containing 16% silicon. This specialized material provides a low thermal expansion rate, allowing for tighter piston-to-cylinder clearances that are ideal for air-cooled engines.
Designed to deliver an 8.6:1 compression ratio with an 80cc head chamber volume, this kit is an ideal direct replacement for OEM part #21941-83. The complete package comes ready for assembly with two pistons, matching rings, wrist pins, and clips.
Key Features
| Brand | Keith Black Pistons |
| MPN | KB258.005 |
| Product Type | Pistons |
| Piston Top Style | Flat Top |
| Bore Size | 89 mm |
| Stroke | 108 mm |
| Compression Ratio | 8.6:1 (with 80cc chamber volume) |
| Material | Hypereutectic Alloy (16% silicon content) |
| Replaces OEM # | 21941-83 |
| Product Weight | 1.2 kg |
Highlights
- Cast hypereutectic alloy with 16% silicon content
- Low thermal expansion rate allows tighter operating clearances
- Designed for air-cooled Evo Big Twin engines
- 8.6:1 compression ratio with standard 80cc combustion chambers
Compatibility
Fits Harley-Davidson Big Twin models from 1984 through 1999 equipped with the Evolution (Evo) engine.
What's included
- 2 x Keith Black Hypereutectic Pistons
- 1 x Piston Ring Set
- 2 x Wrist Pins
- 4 x Retaining Clips
Downloads
Frequently asked questions
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