S&S Cycle 910-0739 Big Bore Cylinder Set 4.250" Black M8

The S&S Cycle 910-0739 is a bolt-in Big Bore Cylinder Set designed for Harley-Davidson Milwaukee-Eight (M8) engines. Featuring a 4.250-inch bore — the largest possible without requiring case machining — this kit delivers a significant displacement increase for riders seeking more power from their stock platform.

The cylinders are finished in a wrinkle black powder coat with non-highlighted fins, giving your engine a clean, blacked-out appearance. Forged pistons are included and deliver the strength needed to handle the added stress of increased displacement at a 10.5:1 compression ratio.

Key Features:

• 4.250 in. bore — maximum bolt-in size, no case machining required
• Wrinkle black powder-coat finish with non-highlighted fins
• Forged pistons for enhanced strength and durability
• 10.5:1 compression ratio
• Compatible with both 107 and 114 M8 engine models
• Includes all gaskets and hardware required for installation
• Bolt-on design — no need to split or bore existing cases
• Made in the USA

This cylinder set is a complete bolt-on upgrade that includes all necessary gaskets and installation hardware. Professional installation by a skilled technician is recommended. All assembly clearances and specifications should be verified during installation.