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