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, all