Go big or go home. With the largest displacement of any Harley-Davidson Stage Kit, this 114CI to 131CI Stage IV Kit was designed to deliver maximum horsepower – all the way to the redline. Packaged with patent-protected cylinder technology, it allows for the largest bolt-on engine upgrade to any Milwaukee-Eight motor. Features new CNC-ported heads with 1mm bigger valves and fully machined combustion chambers. Coupled with the kit's high-lift SE8-517 cam, high compression pistons and a 64mm throttle body and intake manifold, this combination delivers a thrilling 131 ft-lb of torque and 121 HP rear-wheel output when paired with Screamin' Eagle Street Cannon Mufflers. It’s designed to run wide open at high-end RPMs and provide a significant boost of torque from cruising speed. You’ll feel the difference as soon as you twist the throttle. When installed by an authorized Harley-Davidson Dealer within 60 days of the vehicle purchase, compliant kits do not impact the vehicle’s limited warranty. Kit includes: CNC Ported Cylinder Head with CNC machined chamber and 1mm larger valves, Stage IV Timer Cover, SE8-517 High-Lift Cam, Forged High Compression Pistons, High Performance Cam Bearing and Tappets, 4.31" Steel Sleeve Cylinders, 64mm Throttle Body and Cast Manifold and High Flow Injectors (5.5 g/sec).

• Stage IV Kit - 114CI or 117CI to 131CI for Oil Cooled models

• Delivers increased response throughout the entire RPM range

• Provides thrilling acceleration when twisting the throttle

• Maintains flat torque curve from cruising RPM to redline

• Can be installed without removing the engine from chassis

• Retains Original Equipment Factory Warranty

• 49-State U.S. EPA Compliant on '17-later Touring models