Keith Black KB 107 Inch Twin Cam Forged Piston Set for Harley FXST/FLST

Designed for 1999–2006 Harley-Davidson FXST/FLST models, the Keith Black KB 107 Inch Twin Cam Forged Piston Set uses a stock stroke and a 10.5:1 compression ratio with a 4.125-inch piston diameter to deliver improved combustion efficiency and durable performance.

The kit includes the piston, rings, circlips, and pins, plus accessory items needed for a complete rebuild: a ring compressor tool, wrist pin lock, and top end gasket kit. This forged piston set weighs approximately 23 ounces (651 grams) for a balanced combination of strength and lightness, helping improve engine response during acceleration and cruising.

• Piston diameter: 4.125 inches
• Compression ratio: 10.5:1
• Stroke: stock
• Weight: ~651 g (23 oz)
• Material: Forged
• Country of origin: USA
• Included accessories: ring compressor tool, wrist pin lock, top end gasket kit
• Compatible models: Harley-Davidson FXST, FLST, FXD, and FLT from 1999 to 2006 (FXST/FLST range)

Installation instructions are available online. Plan for a break-in period of at least 500 miles at moderate speeds to ensure proper piston and ring seating.

Forged piston set has a compression ratio of 10.5:1 and is for a stock stroke. Set includes rings circlips and pins.

Upgrade your Harley Davidson twin cam engine with the Keith Black KB 107 Inch Forged Piston Set, designed for optimal performance and durability. Crafted in the USA, this piston kit features a precision measure of 4.125 inches utilizing the stock stroke, ensuring a perfect fit for a range of Harley Davidson FXST and FLST models from 1999 to 2006. The piston weighs approximately 23 ounces (651 grams), providing a solid balance between strength and lightweight performance for enhanced engine response.
Installation instructions are available online to guide you through the proper fitting process, emphasizing the importance of a moderate break-in period of at least 500 miles at moderate speeds, avoiding excessive running in lower gears to ensure proper piston and ring seating.
The kit includes all necessary components for a complete rebuild, including the piston itself and recommended accessory items such as the ring compressor tool, wrist pin lock, and top end gasket set. This ensures a comprehensive upgrade that improves engine efficiency and longevity.
Whether you're rebuilding your Harley or looking to boost performance, the Keith Black KB 107 Inch Twin Cam Forged Piston Set offers reliable quality and precise engineering to meet the demands of demanding riding conditions and high-performance applications. Trust in Keith Black’s reputation for manufacturing high-quality engine components that deliver consistent and dependable results.

Features:

• Piston Diameter: 4.125 inches, utilizing stock stroke for seamless fit

• Weight: Approximately 651 grams (23 ounces) for optimal balance

• Material: Forged construction for strength and durability

• Country of Origin: Made in the USA

• Fitment: Compatible with 1999-2006 Harley Davidson FXST and FLST models

• Included Accessories: Ring compressor tool, wrist pin lock, and top end gasket kit

Fitment:
Harley Davidson FLST 1999
Harley Davidson FLST 2000
Harley Davidson FLST 2001
Harley Davidson FLST 2002
Harley Davidson FLST 2003
Harley Davidson FLST 2004
Harley Davidson FLST 2005
Harley Davidson FLST 2006
Harley Davidson FLT 1999
Harley Davidson FLT 2000
Harley Davidson FLT 2001
Harley Davidson FLT 2002
Harley Davidson FLT 2003
Harley Davidson FLT 2004
Harley Davidson FLT 2005
Harley Davidson FLT 2006
Harley Davidson FXD 1999
Harley Davidson FXD 2000
Harley Davidson FXD 2001
Harley Davidson FXD 2002
Harley Davidson FXD 2003
Harley Davidson FXD 2004
Harley Davidson FXD 2005
Harley Davidson FXD 2006
Harley Davidson FXST 1999
Harley Davidson FXST 2000
Harley Davidson FXST 2001
Harley Davidson FXST 2002
Harley Davidson FXST 2003
Harley Davidson FXST 2004
Harley Davidson FXST 2005
Harley Davidson FXST 2006