Stage IV tuning.

Harley-Davidson announced the launch of a new collection of parts and accessories for its Screamin’ Eagle Milwaukee Eight lineup. The two available kits allow the owner to increase their bike’s displacement and... musicality—in compliance with U.S. noise regulations, of course

The first kit is the Screamin’ Eagle 128 Stage IV kit. As the name suggests, this package allows owners of 107 models to modify their motorcycle’s displacement and increase it to 128 cubic inches (so from 1,753cc to 2,097). It includes new CNC ported cylinder heads and chambers with high-compression pistons and 1-mm bigger valves, a 128 Stage IV Timer cover, and a high-lift cam, combined with a collection of Screamin’ Eagle high-performance cam bearing and tappets, steel sleeve cylinders, 64-mm throttle body and manifold, and high-flow injectors.  

According to Harley, this kit is designed to give the 107 models more high-end grunt and will allow the engine to produce 121 horsepower and 126 lb-ft of torque (at the rear wheel), paired up with the Screamin’ Eagle Street Cannon mufflers 

The second kit is for the bigger 114 and 117 blocks. The Screamin’ Eagle 131 Stage IV kit boosts their displacement to, well, 131 cubic inches (or 1,868/1,917cc to 2,146). It includes the same components as the 128 kit with the exception of a 131 Stage IV Timer cover instead. In this case, the 131 kit allows the two bigger Screamin’ Eagle engines to produce 121 horsepower and 131 lb-ft of torque (also at the wheel and with the matching cannon mufflers).  

Harley-Davidson specifies that the kits are not meant to be fitted on the trikes and that depending on the motorcycle’s model-year, additional components such as a high-capacity oil pump and clutch plate kit is required. The Motor Company suggests that interested Screamin’ Eagle owners contact their H-D dealer for further information on the kits’ installation requirements.