S&S Cycle M8 Big Bore Kit - 4.25" Bore - 128ci - Black - 310-1103C

Elevate your Harley-Davidson Milwaukee-Eight engine's performance with the S&S Cycle 128" Power Package. This comprehensive big bore kit is engineered to transform your 114" or 117" CVO engine into a formidable 128" powerhouse, delivering a substantial increase in displacement and raw power.

Description

The S&S Cycle 128" big bore kit is meticulously designed to provide a significant performance boost for your Harley-Davidson Milwaukee-Eight engine. This comprehensive performance kit converts 114" and 117" CVO models to a commanding 128" displacement, ensuring a dramatic increase in horsepower and torque. Engineered for a straightforward installation, this bolt-in kit eliminates the need for complex case machining, making it an accessible upgrade for experienced mechanics and enthusiasts alike. At its core, the kit features robust forged pistons, built to withstand the demands of high-performance riding and deliver exceptional durability. With an impressive 11.1:1 compression ratio, this S&S Cycle engine upgrade optimizes combustion efficiency for explosive power delivery. The package includes essential components such as an S&S oil pump/cam plate, Quickee pushrods with chrome covers, high-quality tappets and cuffs, an S&S 550 camshaft, and heavy-duty valve springs, all meticulously selected to work in harmony and maximize your engine's potential. The black finish with highlighted fins adds a custom aesthetic to your oil-cooled Milwaukee-Eight.

Features & Highlights

• Converts 114" and 117" CVO Milwaukee-Eight engines to a powerful 128" displacement, offering a substantial boost in horsepower and torque for an exhilarating ride.
• True bolt-in design means no case machining is required, simplifying installation and reducing labor time and costs for a hassle-free upgrade.
• Equipped with high-strength forged pistons, engineered for superior durability and reliability under extreme performance conditions.
• Includes a comprehensive S&S performance package: an S&S oil pump/cam plate, Quickee pushrods with stylish chrome covers, premium tappets, tappet cuffs, an aggressive S&S 550 camshaft, and robust valve springs.
• Achieves an impressive 11.1:1 compression ratio, optimizing engine efficiency for crisp throttle response and increased power output across the RPM range.
• Features a sleek black finish with highlighted fins, adding a distinctive custom look to your engine while ensuring optimal performance.

Technical Specifications

• Brand: S&S Cycle
• Model: Power Package
• Product Name: Performance Kit
• Units: Kit
• Displacement: 128 cubic inches
• Bore Size: 4.250"
• Stroke Length: 4.500"
• Compression Ratio: 11.1:1
• Cam Drive Type: Chain
• Cooling System: Oil Cooled
• Color/Finish: Black, Highlighted Fins
• Vendor Part Number: 310-1103C
• MPN/SKU: 09040130

Important to Know

• Not for 121" CVO models.
• Not for any Trike models.
• Intake/rocker cover gaskets not included (required for installation).