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.
- 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.
- 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.
- A high-lift cam controls the valves. Harley-Davidson’s SE8-517 cam does the work.
- 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.
- 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.”
- 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
- 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.
- 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.
