S&S Cycle 129" Power Package Big Bore Kit for M8 107"

Unleash the full potential of your Harley-Davidson® Milwaukee-Eight® 107" engine with the S&S Cycle 129" Power Package Big Bore Kit. This comprehensive, bolt-on upgrade transforms your M8 into a formidable 129" powerhouse, delivering significant gains in horsepower and torque without requiring any case machining.

Description

Designed for motorcycle enthusiasts seeking a substantial performance boost, the S&S Cycle 129" Power Package is a complete bolt-on solution to elevate your 107" Milwaukee-Eight® engine. This kit features high-quality 4.32" bore cylinders paired with robust 11.0:1 compression ratio forged pistons, meticulously engineered to achieve a 129" displacement. The heart of this upgrade includes an S&S oil pump and cam plate, finished with a distinctive blue anodized coating, ensuring superior lubrication and engine longevity. It boasts independent scavenge sections for both the flywheel cavity and cam chest, alongside debris screens and a magnet in the cam chest to prevent harmful particles from entering the oil system. Oil flow capacity is significantly increased on both the feed and scavenge sides, while an adjustable pressure relief valve allows for fine-tuning even after installation. The kit is further enhanced with S&S Quickee pushrods, premium tappets, and hard-anodized, black-coated billet aluminum tappet cuffs. Performance is amplified by S&S 550 cams, specifically designed for big bore applications, and high-performance conical single-wire valve springs capable of handling cams up to 0.605" lift. Proudly Made in the USA, this S&S Cycle big bore kit is compatible with VVT models, offering a premium upgrade for your M8.

Features & Highlights

• Effortless Power Upgrade: Transform your 107" Milwaukee-Eight® engine into a massive 129" displacement with 4.32" bore cylinders and 11.0:1 compression ratio forged pistons, all through a straightforward bolt-on installation that requires no case machining.
• Optimized Engine Longevity: Features an S&S oil pump and cam plate with a blue anodized finish, incorporating independent scavenge sections, debris screens, and a cam chest magnet to ensure superior oil cleanliness and component protection.
• Enhanced Oil System Performance: Benefit from increased oil flow capacity on both the feed and scavenge sides, plus an adjustable pressure relief valve that can be fine-tuned while installed in the engine for optimal lubrication.
• High-Performance Valvetrain: Includes S&S Quickee pushrods, premium tappets, and hard-anodized, black-coated billet aluminum tappet cuffs for reliable, high-lift operation.
• Big Bore Specific Cams: Equipped with S&S 550 cams, precisely designed to maximize the performance of big bore applications, complemented by high-performance conical single-wire valve springs supporting up to 0.605" lift.
• American-Made Quality: Experience superior craftsmanship and reliability with components proudly Made in the USA.

Technical Specifications

• Brand: S&S Cycle
• Product Name: Power Package
• Model: Performance Kit (550C)
• Displacement: 129"
• Bore Size: 4.32"
• Stroke Length: 4.375"
• Compression Ratio: 11.0:1
• Cam Drive Type: Chain
• Cam Lift Support: Up to 0.605"
• Cooling System: Oil Cooled
• Color/Finish: Non-Highlighted Fins, Wrinkle Black
• Features: Black Pushrod Tubes, Cam Chain Tensioner
• Units: Kit
• Vendor Part Number: 310-1226D

Important to Know

• Not for any Trike models.
• Intake/rocker cover gaskets not included.