Harley-Davidson’s Milwaukee Eight Engine Debuts

Cycle News Staff | August 23, 2016

Today, Harley Davidson released the ninth engine in its history, the Milwaukee Eight. The name “Eight” should be a dead giveaway as it denotes the engine will sport eight valves, much like the board track racers of early last century.

Harley-Davidson also released details of new suspension for the 2017 models, which Cycle News will be riding next week just out of Seattle.

“These are the most powerful, most responsive and most comfortable Touring motorcycles ever offered by Harley-Davidson,” said Scott Miller, Vice-President of Styling and Product Development Strategy. “The unmistakable look, sound and feel of Harley-Davidson Touring motorcycles rise to even greater heights with the improvements we’ve made this year.”

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New Milwaukee-Eight Engine

The new Milwaukee-Eight engine is a clean-sheet design that aims to combine the classic look, sound and feel of Harley-Davidson Big Twin engines with improvements in every aspect of engine performance.

“The Milwaukee-Eight engine carries the legacy of Harley-Davidson Big Twins into the future,” said Alex Bozmoski, Harley-Davidson Chief Powertrain Engineer, who led the development team. “While respecting the essential Big Twin character, we’ve created an all-new motor. Every aspect of performance, durability and styling has been improved as a direct response to the voice of Harley-Davidson customers around the world.”

Retaining the classic 45-degree V-Twin cylinder angle, the Milwaukee-Eight engine produces 10 percent more torque than previous year models and features four-valve cylinder heads that offer 50 percent more intake and exhaust flow capacity. The Milwaukee-Eight engine is counter-balanced to cancel 75 percent of primary vibration at idle, retaining the feel of a Harley® V-Twin while being very smooth at highway speeds. A new heat management strategy for all Milwaukee-Eight engines improves rider and passenger comfort.

Milwaukee-Eight engines are offered in two displacements:

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2017 Harley-Davidson Road Glide Special.

 Milwaukee-Eight 107 (107 CID, 1750cc) featuring precision oil-cooled cylinder heads for the Street Glide®/Street Glide® Special, Road Glide®/Road Glide Special®, Electra Glide® Ultra Classic®, Road King® and Freewheeler® models.

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2017 Harley-Davidson Road Glide Ultra.

Twin-Cooled™ Milwaukee-Eight 107 (107 CID, 1750cc) featuring liquid-cooled cylinder heads for the Ultra Limited/Ultra Limited Low, Road Glide® Ultra and Tri Glide® Ultra models.

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2017 Harley-Davidson CVO Limited.

Twin-Cooled Milwaukee-Eight 114 (114 CID, 1870cc) featuring liquid-cooled cylinder heads for the CVO™ Limited and CVO™ Street Glide® models.

More Power

Each Milwaukee-Eight engine produces 10 percent more torque than the engine it replaces in Touring models. In addition to increased displacement, the Milwaukee-Eight engine features a higher compression ratio and four-valve cylinder heads with 50 percent more intake and exhaust flow capacity. The valve train requires no adjustment as the design of the rocker arms enables valve lash to be set at the factory for life. Dual spark plugs for each cylinder contribute to more-efficient combustion. A single chain-driven camshaft is lighter, mechanically less complex and creates less friction and noise.

Quicker Acceleration

The Milwaukee-Eight engine weighs the same as the engines it replaces, so all of its extra power contributes directly to improved acceleration performance. According to H-D, the Milwaukee-Eight 107 accelerates 11 percent quicker 0-60 mph, equal to a two to three bike length improvement, and 11 percent quicker from 60-80 mph in top gear, equal to a one to two bike length improvement, compared to the Twin Cam High Output 103. The Milwaukee-Eight 114 is claimed to accelerate 8 percent quicker 0-60 and 12 percent quicker 60-80 than the Twin Cam 110™.

Heat Management

The Milwaukee-Eight engine offers improved rider and passenger thermal comfort due to reduced heat absorption, increased heat rejection and a redesigned exhaust system. Each Milwaukee-Eight engine features a precision cooling strategy based on the specific demands of the motorcycle model, using a targeted flow of either oil or liquid coolant around the hottest areas of the cylinder heads. A new knock sensor for each cylinder enables more-precise timing control. The rear exhaust pipe is re-positioned and the exhaust catalyst is relocated to move heat away from the passenger. Idle speed is lowered from 1,000 rpm to 850 rpm.

Improved Fit

A new, slimmer primary drive cover and the low-profile shape of the air cleaner cover provide improved rider legroom around the engine and an easier reach to the ground for many riders. All Milwaukee-Eight powered models are fitted with an Assist and Slip Clutch with improved hydraulic actuation that reduces clutch lever effort by 7 percent.

Reduced Vibration

The rubber-mounted Milwaukee-Eight engine features a single internal counter balancer that cancels 75 percent of primary vibration at idle for a more-refined feel and more-comfortable experience for rider and passengers while retaining the character of Harley® V-Twin engines.

Richer Exhaust Note

Lighter valves, a single camshaft, optimized cover designs and improved driveline components eliminate much of the mechanical powertrain noise. The engine intake and air cleaner are designed to reduce intake sound while ensuring maximum air flow. As a result, the new Milwaukee-Eight engine is mechanically quieter, enabling a richer exhaust tone, and meets all global noise and emissions standards while allowing the rumble of its exhaust note to resonate.

Improved Charging

The Milwaukee-Eight engine charging system delivers 50 percent more output to the battery at idle to better support the power demands of Touring riders, including accessory lighting, performance audio, and heated gear and other accessories.

New Engine Styling

The Milwaukee-Eight engine features sleek, modern styling that respects the heritage of previous Harley-Davidson Big Twin engines. “The Milwaukee-Eight engine is styled to project power,” said Brad Richards, Harley-Davidson Director of Styling. “I compare it to the back of a swimmer, lean in the waist but broad and muscular in the shoulders. The rocker covers look like skin stretched taut over muscle, like the rocker arms are about to burst out of the engine,” said Richards. “For the first time since the Knucklehead, the rocker covers reflect the action going on below. And they are massive. When you sit on the bike you can look down and see more of this engine.”

New Touring Suspension

All-new front and rear suspension components enhance the comfort, control and performance of all 2017 Harley-Davidson® Touring model motorcycles. New emulsion-technology rear shock absorbers offer 15 to 30 percent more pre-load adjustment than previous standard Touring shocks, with a single knob to hydraulically adjust pre-load.

“Pre-load can now be adjusted to match the load of rider, passenger and gear without tools or an air pump,” said Paul James, Harley-Davidson Director of Motorcycle Product Planning. “Once set, the pre-load will not leak down or require further adjustment.”

The front suspension features new Showa® SDBV™ suspension technology that delivers the damping performance of a racing-style cartridge fork with linear damping characteristics and reduced weight.

Screamin’ Eagle® Performance

Harley-Davidson Screamin’ Eagle® Performance will offer a full selection of street-legal performance components for the Milwaukee-Eight engines, including Screamin’ Eagle® Milwaukee-Eight™ Stage I, II and III kits that deliver up to a 24 percent increase in torque over the stock engine.

Harley-Davidson Custom Vehicle Operations (CVO)

Harley-Davidson® Custom Vehicle Operations™ (CVO) models combine prestige and performance in three limited-edition factory-custom motorcycles for 2017.

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  • The 2017 CVO™ Limited model gets the new Twin-Cooled Milwaukee-Eight 114 engine and improved ride and handling provided by the new suspension. Also new for 2017 are Contrast Chrome Slicer wheels and a seat reshaped for rider comfort. The CVO Limited also features a new custom paint scheme in four new color combinations.
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  • The 2017 CVO™ Street Glide gets the new Twin-Cooled Milwaukee-Eight 114 engine, new suspension, and a four-speaker, 600-watt Boom! Audio system. Also new for 2017 are power locks for the saddlebags and fork controlled by a single security and locking key fob, and a re-styled seat cover. The CVO Street Glide is available in four new color combinations for 2017.
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  • The 2017 CVO™ Pro Street Breakout brings a darker look to the CVO line. The CVO Pro Street Breakout is powered by the Screamin’ Eagle® Twin Cam 110B™ air-cooled V-Twin engine. Three finish choices include the new Starfire Black/Scorched Apple combination.
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2017 Harley-Davidson Street 500/750 Motorcycles

2017 Harley-Davidson Street® motorcycle models are available with ABS (Anti-Lock Braking System) and the Harley-Davidson Smart Security System with hands-free, proximity-based security fob, each as a factory-installed option. New optional two-tone paint schemes for the 2017 Street 750 include Vivid Black Deluxe and Velocity Red Sunglo Deluxe for North America and Vivid Black Deluxe and Fire Red Deluxe for Asia, Europe and Latin America.

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Powerful Cruiser Lineup

With the High Output Twin Cam 103™ standard for all 2017 Softail® models and Dyna® models except the Street Bob® model and the S Series cruisers with the Screamin’ Eagle® Twin Cam 110™ engine, Harley-Davidson continues to offer its most powerful cruisers ever.

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