While the Milwaukee-Eight 107 and 114 motors are capable of more than enough performance to satisfy any reasonable Harley-Davidson Softail owner, that doesn’t mean that sometimes you just want more. For 2021, there are two new Screamin’ Eagle Milwaukee-Eight Stage III Kits for Softails to bulk up the performance significantly. We have eight fast facts to get you up to speed.
- The two Screamin’ Eagle Milwaukee-Eight Stage III Kits for Softails rely exclusively on a bore increase to 4.155 inches. As a result, the 107ci to 119ci kit has the same parts as the 114ci to 122ci kit. The 107 retains a stroke of 4.374 inches, while the 114 continues to have a 4.5-inch stroke.
2. Because the 107 gets a larger displacement bump than the 114, it also enjoys a more substantial performance gain. The 107ci to 119ci kit increases horsepower by 23 percent and torque by 17 percent. The boost is more modest on the 114ci to 122ci kit, which escalates horsepower by 14 percent and torque by 13 percent. Still, the Screamin’ Eagle Milwaukee-Eight Stage III 122 motor will put our more grunt than the 119, though the gap will be narrower than between the Milwaukee-Eight 114 and 107 engines. The saying holds true—there’s no replacement for displacement.
3. The larger bore also means higher compression. Screamin’ Eagle Forged 11.0:1 High-Compression Pistons and Rings slip inside the Screamin’ Eagle 4.1555 Big Bore Bolt-On Cylinders. To simplify installation, the Screamin’ Eagle cylinders can be installed without pulling the motor—a considerable time and money saver.
4. Torque is king, and the Screamin’ Eagle SE8-447 Torque Cam makes sure there’s plenty of pull. According to a Harley-Davidson spokesman, the kits “deliver increased throttle response throughout the entire rpm range” and “produces flexible roll-on passing power, reducing the need to downshift.” Drag fans will want to know that Harley-Davidson tells us that the kits “deliver excellent stop-light to freeway speed on-ramp acceleration.”
5. In addition to the major power-producing parts, there are several ancillary parts to complete the kit:
- Screamin’ Eagle High-Capacity Tappets
- Screamin’ Eagle High-Performance Cam Bearing
- Screamin’ Eagle Stage III Timer Cover and Insert
- Multi-layer coated head gaskets
- Most necessary gaskets and seals, including cylinder base and cam cover gaskets
6. If you purchase either Screamin’ Eagle Milwaukee-Eight Engine Stage III kit within 60 days of buying your Softail, it has a two-year vehicle limited warranty. If the kit is installed on a motorcycle owned for more than 60 days, you get a one-year warranty.
7. Harley-Davidson owners in California might want to think about moving to another state. The Screamin’ Eagle Milwaukee-Eight Stage III Kits for Softails are only legal in 49 states. Guess which state is the exception.
8. The MSRP for either Screamin’ Eagle Milwaukee-Eight Stage III Kit is $1800.