More power, more torque, better throttle response, a smoother ride – characteristics Harley-Davidson promises will be apparent to riders with its new Milwaukee-Eight engines. The ninth generation of Motor Company Big Twins, Milwaukee-Eight engines will power all HD Touring and Trike models in 2017.
The Milwaukee-Eights will come in two displacements, 107 cubic inches (1750cc) and 114 cubic inches (1870cc), and three configurations. Two feature the twin-cooling (liquid-cooling) method first unveiled in mid-2013 as part of Harley’s Project Rushmore; the Twin-Cooled Milwaukee-Eight 107 and Twin-Cooled Milwaukee-Eight 114. The third version, the Milwaukee-Eight 107, is cooled only by oil and air.
Here’s the full breakdown of models classified by engines in 2017, provided courtesy of Harley-Davidson:
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.
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.
Twin-Cooled Milwaukee-Eight 114 (114 CID,1870cc) featuring liquid-cooled cylinder heads for the CVO Limited and CVO Street Glide models.
The updated engines were created using input from riders across the world according to Harley-Davidson Vice-President of Styling and Product Development Strategy, Scott Miller:
“The guiding principle behind the Milwaukee-Eight engine was our voice of customer research from every region of the world. Riders asked us to create a new engine designed to enhance their motorcycle touring experience in every way. Those same voices also demanded that we stay true to our legacy and respect the defining elements of a Harley-Davidson V-Twin. It was a big challenge, but one we’ve met. With the Milwaukee-Eight, a new era of Harley-Davidson power, performance and innovation has been forged.”
Harley-Davidson Chief Powertrain Engineer Alex Bozmoski offered a statement as well:
“The Milwaukee-Eight engine retains the classic Harley-Davidson 45-degree V-Twin design. 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.”
Beyond upping displacement, Harley increased the compression ratio and upped the flow capacity of the intake and exhaust systems. It also highlights the combustion efficiency of its dual spark plug set-up (per cylinder) and the friction loss achieved with its updated single chain-driven camshaft. Harley also promises zero need for valve train adjustments, owing to a rocker arm design which “enables valve lash to be set at the factory for life.”
The gains promised by the Motor Company include 10 percent more torque than the outgoing High Output Twin Cam engines being replaced in Touring models. HD also says that the Milwaukee-Eight 107 will accelerate 11 percent faster 0-60mph, and be 11 percent faster from 60-80mph in top gear. For the Milwaukee-Eight 114, gains are said to be eight percent faster 0-60mph and 12 percent faster from 60-80mph.
A smaller profile air cleaner trims the overall shape of the mills for more legroom and easier reach to the ground. Each Milwaukee-Eight engine also comes with a single internal counter balancer for a promised 75 percent reduction in vibration at idle, the speed of which has been reduced from 1000rpm to 850rpm.
One particularly nice feature of the new Milwaukee-Eight engines is the promised heat reduction thanks to the cooling and changed exhaust systems. Each cylinder now carries a new knock sensor for more accurate timing control and the exhaust catalyst is positioned differently to direct heat away from the passenger more efficiently.
Despite all the changes, Harley promises that the exhaust note remains as thunderous as ever. The Milwaukee-Eight engines’ look was a point of particular focus as well. Harley-Davidson Director of Styling Brad Richards put it this way:
“The Milwaukee-Eight engine is styled to project power. 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. 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.”