Screamin’ Eagle Milwaukee-Eight 131ci Stage IV Kit for Softails (8 Fast Facts)

There is now a Harley-Davidson Screamin’ Eagle 131ci engine kit for selected Softail motorcycles running Milwaukee-Eight 114ci and 117cc motors. The Stage IV Kit creates massive torque and the ability to operate effectively at high rpm. Let’s take a look at the fast facts.

  1. Harley-Davidson claims the Stage IV Kit puts out 124 horsepower at the rear wheel, along with 135 ft-lbs of torque. To get there, however, you have to add the Screamin’ Eagle Street Cannon Mufflers. Also, the Motor Company doesn’t quote rpm to match the peak numbers.
  1. The Kit includes CNC-ported heads. The combustion chambers are fully machined, and the valves are 1mm larger in diameter than used in the previous Stage IV kit.
  1. A high-lift cam controls the valves. Harley-Davidson’s SE8-517 cam does the work.
  1. High compression pistons are fed by a cavernous 64mm throttle body. The Harley-Davidson 131ci Stage IV kit also has its own intake manifold and injectors that flow 5.5 grams per second.
  1. Harley-Davidson boasts that the 131ci Stage IV Kit is “designed to deliver maximum horsepower all the way to the redline.” A spokesman goes on to say that “It’s designed to run at high-end rpm and provide a significant boost of torque from cruising speed. You’ll feel the difference as soon as you twist the throttle.”

Screamin' Eagle 131ci Kit: Parts, Prices

  1. Here is a rundown of the performance parts that come with the Harley-Davidson 131ci Stage IV Kit:
  • Screamin’ Eagle CNC Ported Cylinder Head w/ CNC-machined chamber and 1mm larger valves than the previous generation
  • Screamin’ Eagle High Performance Tappets
  • SE8-517 High-Lift Cam
  • Screamin’ Eagle High Performance Cam Bearing
  • Screamin’ Eagle 4.31” Steel Sleeve Cylinders
  • Forged 10.7:1 High Compression Pistons
  • Screamin’ Eagle 64mm Throttle Body and Cast Manifold
  • Screamin’ Eagle High Flow Injectors (5.5 g/sec)
  • 131 Stage IV Timer cover
  1. If you buy the Kit with a new motorcycle, Harley-Davidson warrantees it for 24 months when the dealer installs it. On a Softail over 60 days old, the warranty runs 12 months.
  1. There’s no price yet on the Harley-Davidson 131ci Stage IV Kit for Softails, but look for it to run about $3500. We’re also waiting on a list of compatible Softails, though the motor modded must be a Milwaukee-Eight 114 or 117.