S&S Cycle 910-0684A Big Bore Cylinder Kit Wrinkle Black Highlighted Fins - 128 M8

The S&S Cycle 910-0684A is a premium 128 cubic inch big bore cylinder and piston kit designed for Harley-Davidson Milwaukee-Eight engines with 114" or 117" displacement. This bolt-on performance upgrade features wrinkle black cylinders with highlighted cooling fins for an aggressive custom look.

Key Features:

• 4.250" bore diameter for maximum displacement increase
• Compatible with stock 4.5" stroke M8 engines
• Forged pistons with 10.5:1 compression ratio
• Bolt-on installation - no case machining or splitting required
• Updated cylinder profile fits both Gen 1 and Gen 2 M8 models
• Works with stock crankcases and cylinder heads
• Premium aluminum castings with cast-in iron liners
• Includes cylinders, pistons, rings, gaskets, and installation hardware
• Made in the USA

This kit transforms your 114" or 117" Milwaukee-Eight into a powerful 128 cubic inch powerplant while maintaining stock engine height. The highlighted fins add visual appeal while the increased displacement delivers impressive performance gains. Compatible with 2017-2025 Touring and 2018-2024 Softail M8 models. Not recommended for FL Trike applications. Not legal for sale or use in California on pollution-controlled vehicles.