128" Big Bore Cylinder Kit for 114" and 117" / M8

The S&S Cycles 128" Big Bore Cylinder Kit is designed to maximize power and torque for Harley-Davidson Milwaukee-Eight 114" and 117" engines. This bolt-on upgrade increases engine displacement without requiring complex machining, making it a top choice for riders seeking enhanced performance.

• Provides excellent performance gains with stock cylinder heads
• No need to bore or split the existing crankcases for installation
• Constructed from premium aluminum castings with cast-in iron liners

How Does This Big Bore Kit Improve Performance?

By increasing bore size and compression, this kit optimizes combustion efficiency, resulting in noticeable horsepower and torque gains.

• Features a 4.250” bore and 4.500” stroke for increased displacement
• Includes 11:1 forged pistons for improved durability and power output
• Comes with all necessary gaskets and hardware for a complete installation

Is the S&S 128" Big Bore Cylinder Kit Easy to Install?

This kit is designed as a bolt-on upgrade, allowing for an easier installation process. However, due to the precision required, a skilled technician is recommended to ensure proper assembly and clearances.

• Requires checking all assembly specifications before installation
• Includes cylinders, pistons, rings, and gaskets for a complete setup
• Made in the U.S.A. with high-quality materials for long-term reliability

Will This Kit Fit Your Harley?

The S&S 128" Big Bore Cylinder Kit is specifically designed for 114" and 117" Milwaukee-Eight engines but is not recommended for H-D FL Trike models.

Upgrade your Harley-Davidson Milwaukee-Eight 114" or 117" engine with the S&S 128" Big Bore Cylinder Kit for a significant boost in power and performance. Order today and take your ride to the next level.