S&S Cycle 131" Stroker Cylinder & Piston Kit for Harley w/ Stroker Flywheel

S&S Cycle has been perfecting big bore kits since the 1960s, turning engine performance into an absolute science. This Stroker Cylinder and Piston Kit is engineered specifically for the Milwaukee-Eight® platform, offering a massive displacement increase that delivers tire-melting power. By combining high-quality forged pistons with precision-engineered 4.250” bore cylinders, this kit creates a solid platform for riders demanding maximum performance from their engine.

Designed to outperform factory components, these kits are built to much tighter tolerances and utilize superior materials. The cylinders feature a powder coat finish designed to match the factory look, providing a "sleeper" advantage while retaining the original engine serial numbers and stock engine height.

Features & Benefits

• Huge displacement increase results in significant power gains
• 4.250" bore with updated profile and stock 4.840" bolt pattern
• Compatible with stock crankcases
• Original engine serial numbers are retained for a seamless upgrade
• Powder coat finish matches factory finish for an integrated look
• Includes .045" MLS (multi-layered steel) head gaskets
• Retains stock engine height for easy installation
• Includes 131" Cam Cover Badge
• Not compatible with 121" CVO models
• Note: Must be used with S&S stroker flywheels to achieve 131" displacement (part #s SS320-0605, SS320-0620)