The all-new Harley-Davidson Milwaukee-Eight engine, the ninth in the lineage of the company’s Big Twin engines, has been revealed. The new engine is claimed to deliver more power and an improved motorcycling experience for riders and passengers while retaining the iconic look, sound and feel of its predecessors. An all-new design, the Milwaukee-Eight engine is said to offer quicker throttle response, more passing power, purer sound, a smoother ride and more of the feeling riders want from a Harley-Davidson Touring motorcycle engine. The Milwaukee-Eight engine features sleek, modern styling that respects the heritage of previous Harley-Davidson Big Twin engines.
The new Milwaukee-Eight engines will power every 2017 Harley-Davidson Touring model and will be offered in two displacements and two variations:
- Milwaukee-Eight 107 (107 CID, 1745cc) featuring precision oil-cooled cylinder heads for the Street Glide Special, Road Glide Special and Road King.
- Twin-Cooled Milwaukee-Eight 114 (114 CID,1870cc) featuring liquid-cooled cylinder heads for the CVO Limited.
Each Milwaukee-Eight engine has been designed to produces 10 percent more torque than the engine it replaces in Touring models (varies per model). In addition to increased displacement, the Milwaukee-Eight engine also 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.
The Milwaukee-Eight engine also weighs the same as the engines it replaces, so all of its extra power contributes directly to improved acceleration performance. 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 accelerates 8 percent quicker 0-60 and 12 percent quicker 60-80 than the Twin Cam 110.
The Milwaukee-Eight engine also 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.
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 is aimed to reduce clutch lever effort by 7 percent.
Vibrations have been taken care of with rubber mounts. The rubber-mounted Milwaukee-Eight engine features a single internal counter balancer that cancels 75 percent of primary vibration at idle for a refined feel and comfortable experience for rider and passengers while retaining the classic character of Harley V-Twin engines.
Lighter valves, a single camshaft, optimized cover designs and improved driveline components eliminate 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 unmistakable rumble of its exhaust note to resonate.
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.
Here is the official promotional video of the new Harley-Davidson Milwaukee-Eight engine: