In 2016, Harley-Davidson introduced the Milwaukee-Eight engine, a completely redesigned V-twin that revolutionized the performance, reliability, and smoothness of Harley’s Big Twin motorcycles. As the ninth-generation Big Twin in Harley history, the Milwaukee-Eight was built to deliver more power, less heat, better fuel efficiency, and a smoother ride—all while keeping the legendary Harley rumble intact.

Why Harley Created the Milwaukee-Eight

Before the Milwaukee-Eight, Harley’s Twin Cam engine (introduced in 1999) was the powerhouse of their touring and big cruiser models. While the Twin Cam was a solid platform, riders had increasing demands for better power, cooling, and comfort—especially with modern emissions regulations.

Harley-Davidson designed the Milwaukee-Eight (M8) to address these needs, bringing:
✔ More Power – Stronger acceleration and torque
✔ Better Heat Management – Cooler ride for the rider and passenger
✔ Smoother Performance – Less vibration and noise
✔ Improved Fuel Efficiency – More miles per gallon
✔ Enhanced Handling – Better frame balance and suspension compatibility

Key Features of the Milwaukee-Eight

1. More Power and Torque

• The Milwaukee-Eight 107 (1,746cc) and 114 (1,868cc) engines debuted in 2017 on Touring models.

• The M8 delivers about 10% more torque than the Twin Cam it replaced.

• With faster acceleration, the Milwaukee-Eight Touring models gained quicker 0-60 mph times and stronger roll-on power.

2. Four-Valve Heads for Better Airflow

• Unlike previous Harley Big Twins, the Milwaukee-Eight features four valves per cylinder instead of two, leading to:

  • 50% better intake and exhaust flow

  • More efficient combustion

  • Stronger throttle response

• Despite more valves, the engine remains mechanically simple and easy to maintain.

3. Improved Cooling System

• The Milwaukee-Eight introduced two cooling options:

  • Oil-cooled heads on standard models

  • Liquid-cooled heads (Twin-Cooled) on premium models

• These advancements reduced engine heat, making long-distance rides more comfortable for both rider and passenger.

4. Reduced Vibration & Smoother Ride

• The Milwaukee-Eight features a single internal counterbalancer, cutting vibrations by 75% at idle while maintaining Harley’s signature pulse.

• This makes long-haul touring less fatiguing without losing that classic Harley feel.

5. Improved Fuel Efficiency & Emissions

• The higher compression ratio and precision cooling made the M8 more fuel-efficient and cleaner-burning, helping Harley meet modern emissions regulations while delivering stronger performance.

Models That Received the Milwaukee-Eight

1. Touring Models (2017-Present)

The Milwaukee-Eight 107 and 114 engines first appeared in the 2017 Harley-Davidson Touring lineup, including:

• Street Glide & Road Glide – More power for highway cruising

• Electra Glide Ultra & Ultra Limited – Improved comfort and heat management

• Road King – Smoother acceleration and torque for long rides

2. Softail Models (2018-Present)

• In 2018, the Milwaukee-Eight replaced the Twin Cam in Softail models, introducing a new chassis and improved suspension.

• Softails like the Fat Bob, Heritage Classic, and Breakout gained the Milwaukee-Eight 107 or 114, offering better ride quality and power.

3. CVO Models (2017-Present)

• CVO (Custom Vehicle Operations) models got the high-performance Milwaukee-Eight 117 (1,923cc) and later the Milwaukee-Eight 121 (1,977cc).

• These engines deliver the most torque and horsepower ever in a stock Harley.

4. Trike Models (2019-Present)

• Harley’s Tri Glide and Freewheeler trikes also received the Milwaukee-Eight, enhancing stability and acceleration for three-wheeled touring.

The Milwaukee-Eight’s Impact on Harley-Davidson

1. Modern Performance with Classic Soul

Harley managed to keep the Milwaukee-Eight true to its heritage—a big, torquey 45-degree V-twin—while making it significantly stronger, smoother, and more reliable.

2. Making Harley’s Touring Bikes More Competitive

With competition from Indian Motorcycle and modern touring bikes from brands like BMW and Honda, the Milwaukee-Eight helped Harley maintain its dominance in the heavyweight touring category.

3. Setting the Stage for Future Harley Engines

The Milwaukee-Eight is the foundation for Harley’s next generation of V-twins, including performance-based Screamin’ Eagle upgrades and the new Revolution Max engine in Harley’s Pan America and Sportster S models.

Final Thoughts: A New Benchmark for Harley’s Big Twins

The Milwaukee-Eight engine represents one of the biggest advancements in Harley-Davidson’s long history of V-twins. By delivering more power, better cooling, smoother performance, and greater fuel efficiency, it ensures that Harley’s Touring and Cruiser models remain relevant, competitive, and enjoyable for modern riders.

While Harley’s signature sound and feel will always be a key part of the brand, the Milwaukee-Eight proves that innovation and tradition can coexist—making it a defining moment in Harley-Davidson’s evolution.