Inspired by the motors built for the MotoAmerica Mission King of the Baggers Championship Series, the new Screamin’ Eagle 135ci Stage IV Performance Crate Engine is here. Built by Harley-Davidson Powertrain Operations, it packs some serious performance numbers. While we’re impressed by the performance of the Milwaukee-Eight 117, this Screaming Eagle 135 absolutely crushes it. Get ready for 143 ft-lbs of torque at the rear wheel at 3500 rpm, and 130 horsepower at 5500 rpm, also measured at the rear wheel. That’s a 28 percent torque peak increase over the 117, and a 41 percent horsepower boost.
Let’s go over what you get with the Harley-Davidson Screamin’ Eagle 135ci Stage IV Performance Crate Engine, starting from the beginning of the combustion process:
- A CNC-machined intake manifold
- A 68mm throttle body
- High-capacity 6.8 gram/second fuel injectors
- Screamin’ Eagle Extreme CNC-ported cylinder heads
- A high-lift SE8-517 cam
- High-performance cam bearing
- High-performance tappets
- High-performance valve springs
- Screamin’ Eagle Pro Billet Cam Plate and Oil Pump
- High-compression 10:7:1 forged pistons
- Steel cylinders measuring 4.31 inches
- A 4.65-inch flywheel
The Harley-Davidson Screamin’ Eagle 135ci Stage IV Performance Crate Engine has a list price of $8000. It is a bolt-on design for 2021-and-newer Harley-Davidson Touring chassis models—sorry, Softail and Trike owners.
Two versions of the crate motor are offered—one for the Touring models with an air-/oil-cooled Milwaukee-Eight engine, and another for the Twin-Cooled Milwaukee-Eight powerplants. If you have a California model, you are out of luck—this is a 49-state build.
You can have the 2212cc Harely-Davidson crate engine finished in Chrome or Black, and 135 Stage IV badging on the timer cover and cylinder heads is standard. If you have a dealer do the installation, you get a two-year warranty.
The kit still requires some additional parts. You’ll need a new Head Pipe, and a Screamin’ Eagle Pro Street Tuner must do an EMC recalibration to keep the motor emissions-compliant. Air-/oil-cooled motor, you’ll need either an Oil Cooler Fan Assist or a Fan for Factory Oil Cooler. You won’t need engine-mount relocation or any fabrication.
For those who want the absolute peak performance from the Harley-Davidson Screamin’ Eagle 135ci Stage IV Performance Crate Engine, The Motor Company recommends getting a Screamin’ Eagle Ventilator Extreme Air Cleaner and Screamin’ Eagle Street Cannon Mufflers.
