Harley-Davidson, Inc. (H-D), or Harley, is an American motorcycle manufacturer, founded in Milwaukee, Wisconsin in 1903.
One of two major American motorcycle manufacturers to survive the Great Depression (along with Indian), the company has survived numerous ownership arrangements, subsidiary arrangements (e.g., Aermacchi 1960-1978 and Buell 1987-2009), periods of poor economic health and product quality, as well as intense global competition to become one of the world's largest motorcycle manufacturers and an iconic brand widely known for its loyal following.
There are owner clubs and events worldwide as well as a company-sponsored brand-focused museum.
Noted for a style of customization that gave rise to the chopper motorcycle style, Harley-Davidson traditionally marketed heavyweight, air-cooled cruiser motorcycles with engine displacements greater than 700 cm³ and has broadened its offerings to include its more contemporary VRSC (2002) and middle-weight Street (2015) platforms.
Harley-Davidson manufactures its motorcycles at factories in York, Pennsylvania; Milwaukee, Wisconsin; Kansas City, Missouri (closing); Manaus, Brazil; and Bawal, India.
Construction of a new plant in Thailand is scheduled to begin in late 2018. The company markets its products worldwide.
The classic Harley-Davidson engines are V-twin engines, with a 45° angle between the cylinders.
The crankshaft has a single pin, and both pistons are connected to this pin through their connecting rods.
This 45° angle is covered under several United States patents and is an engineering tradeoff that allows a large, high-torque engine in a relatively small space.
It causes the cylinders to fire at uneven intervals and produces the choppy "potato-potato" sound so strongly linked to the Harley-Davidson brand.
To simplify the engine and reduce costs, the V-twin ignition was designed to operate with a single set of points and no distributor.
This is known as a dual fire ignition system, causing both spark plugs to fire regardless of which cylinder was on its compression stroke, with the other spark plug firing on its cylinder's exhaust stroke, effectively "wasting a spark".
The exhaust note is basically a throaty growling sound with some popping.
The 45° design of the engine thus creates a plug firing sequencing as such. The first cylinder fires, the second (rear) cylinder fires 315° later, then there is a 405° gap until the first cylinder fires again, giving the engine its unique sound.