The
Harley-Davidson
Harley-Davidson, Inc. (H-D, or simply Harley) is an American motorcycle manufacturer headquartered in Milwaukee, Wisconsin, United States. Founded in 1903, it is one of two major American motorcycle manufacturers to survive the Great Depressi ...
Milwaukee-Eight engine is the ninth generation of "big twin" engines developed by the company, but only Harley's third all-new Big Twin in 80 years, first introduced in 2016. These engines differ from the traditional Harley Big Twin engines in that there are four valves per cylinder, totaling eight valves, hence the name. It also marked a return to the single-camshaft configuration as used on previous Harley Big Twin Engines from 1936 to 1999. In addition, the engines all have internal
counterbalancers, whereas Twin Cams were counterbalanced only on
Softail
A softail (shortened form of ''soft tail'') motorcycle intentionally looks like vintage motorcycles with a rigid hard-tail frame that has a triangle of steel tubes at the rear axle, like on a bicycle frame, but on a Softail these tubes are ...
models, where the engine was rigidly mounted.
107 and 114 and 117 engines
All engines have eight valves in two cylinders in the traditional V-twin configuration at 45°, are combination of air-cooled and oil-cooled, and activate valves with push-rods. The model with a claimed is standard on all models, with the version making a claimed remaining as an option on some softails and all touring and trike models, and the is standard on CVO models with a claimed and rear wheel power of @ 4,870 rpm and @ 3,400 rpm.
Differences from the predecessor (
Twin Cam
An overhead camshaft (OHC) engine is a piston engine where the camshaft is located in the cylinder head above the combustion chamber. This contrasts with earlier overhead valve engines (OHV), where the camshaft is located below the combustion cha ...
)
In 2016, the Milwaukee-Eight engines became available on Touring and Trike models of the 2017 model year. The Softail models started using the Milwaukee-Eight the following year. The most significant change from the Twin Cam are the two extra valves per cylinder head which produce 10 percent more torque. The exhaust and intake flow capacity is increased by 50 percent over the Twin Cam models. Although weighing the same as its predecessor, both models of the Milwaukee-Eight increase in acceleration by 10% (0-60 for the 107 vs the 103) and 8% (0-60 for the 114 vs. the 110). Fuel economy is also increased, with percentages varying for engine and model.
Improvements
Harley conducted interviews in seven cities; over 1,000 people were asked to outline what they would like to see in the next line of touring bikes. These interviews resulted in the new Milwaukee-Eight engine. The biggest improvements people wanted to see were more power, less heat, and less vibration. Harley was able to increase the power while also keeping the range and consumption similar and in some cases making it even better. To deal with the heat issue, Harley reduced the
exhaust gas
Exhaust gas or flue gas is emitted as a result of the combustion of fuels such as natural gas, gasoline (petrol), diesel fuel, fuel oil, biodiesel blends, or coal. According to the type of engine, it is discharged into the atmosphere through an ...
temperature by 100°F (55.6 C), allowing for a more comfortable ride. They were able to make this possible by relocating the hot catalytic converters further from the cockpit, as well as introducing a better water cooling solution. Finally, Harley looked at the vibration issues and decided to reduce the vibrations by 75%, in order to affect a balance between hardcore fans and new Harley owners.
Reception
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Cycle World
''Cycle World'' is a motorcycling magazine in the United States. It was founded in 1962 by Joe Parkhurst, who was inducted to the Motorcycle Hall of Fame as "the person responsible for bringing a new era of objective journalism" to the US. ''Cyc ...
'', like many other motorcycle magazines, was given the opportunity to test ride and review the Milwaukee-Eight engine. The reviews have been positive, and report a better ride quality, while still keeping the Harley feel. Cycle World's reviewer reported a noticeable reduction in the heat output from the engine, enabling the reviewer to ride more comfortably. The review concludes that the changes make this engine an improvement over its predecessor.
References
{{Reflist
Harley-Davidson engines