129" Big Bore Cylinder Kits / '17-'23 107" M8 Motors

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Elevate your Harley's performance to monumental heights with the S&S Cycles 129 Big Bore Kit, the ultimate upgrade for M-Eight 107 engines. Designed for seamless integration, this bolt-on kit is the pinnacle of engine enhancement, offering the largest cylinder bore achievable without the need for crankcase machining.

Key Features:

• Maximized Performance: Achieve a 4.320 bore and 4.375 stroke without altering the crankcase.
• High-Quality Components: Comes with 11:1 forged pistons, ensuring unmatched durability and power.
• Effortless Installation: All necessary MLS (multi-layered steel) head gaskets and hardware included. Original engine serial numbers are retained, and the stock engine height remains unchanged.
• Exclusive Cam Cover Badge: Each kit includes a cam cover badge, adding a mark of distinction to your ride.
• Proudly Made in the U.S.A.: Experience the excellence of American engineering.

Elevate Your Ride without Compromise

The S&S Cycles 129 Big Bore Kit for Harley Davidson M8 motors is not just an upgrade; it's a transformation. Offering the perfect blend of performance, reliability, and style, this kit ensures your Harley stands out both on the road and off it. Retain the essence of your engine while pushing its boundaries.