Harley-Davidson this week unveiled the much-rumoured new engine powering its 2017 touring models — the Milwaukee-Eight series.
The Milwaukee-Eight takes its name from the combined 8 valves residing in the new cylinder heads (4 valves for each cylinder), but there’s more to it than that.
In addition to the valves, displacement has grown from 1687cc to 1745cc for the Milwaukee-Eight 107 and its liquid-cooled twin the “Twin-Cooled” Milwaukee-Eight 107. In addition to the two 107 engines, a larger twin-cooled 1870cc (114cu) version is available for CVO Limited and CVO Street Glide models.
The compression ratio has been increased and the newly designed heads benefit from 50 per cent more intake and exhaust flow capacity thanks to the 4-valve heads. Dual spark plugs for each cylinder contribute to more efficient combustion. The chain-driven camshaft is lighter, mechanically less complex and creates less friction and noise.
“The Milwaukee-Eight engine retains the classic Harley-Davidson 45-degree V-Twin design,” said Alex Bozmoski, Harley-Davidson Chief Powertrain Engineer, who led the development team. “It also retains the power characteristic that is the real legacy of the Harley-Davidson Big Twin: strong, low-end torque with a broad, flat power curve through the mid-range that’s ideal for the Touring motorcycle rider.”
The new engine is the ninth in the lineage of the company’s iconic Big Twin engines and delivers where it counts most — performance.
Producing around 10 per cent more torque than the engines in 2016 touring range, the Milwaukee-Eight 107 accelerates 11 per cent faster in 0-100 km/h testing compared to the 2016 models, which have the Twin Cam High Output 103 engine. “The guiding principle behind the Milwaukee-Eight engine was our voice of customer research from every region of the world,” said Scott Miller, Harley-Davidson vice-president of styling and product development strategy.
Lighter valves, a single camshaft, optimised cover designs and improved driveline components eliminate mechanical powertrain noise. The engine intake and air cleaner have been designed to reduce intake sound while still ensuring air flow. As a result, the the company says the new engine is mechanically quieter, with a richer exhaust tone. Importantly it also meets all global noise and emissions standards. The global press launch for the Harley-Davidson MY17 models early next month will feature the Milwaukee-Eight engines. Driven will be there to put them to the test.