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The knucklehead is a retronym used by enthusiasts to refer to a Harley-Davidson motorcycle engine, so named because of the distinct shape of the rocker boxes.The engine is a two-cylinder, 45 degree, pushrod actuated overhead valve V-twin engine with two valves per cylinder. It was the third basic type of V-Twin engine used by Harley-Davidson, replacing the Flathead-engined VL model in 1936 as HD's top-of-the-line model. The engine was manufactured until 1947 and was replaced by the Panhead engine in 1948. The Knucklehead-engined models were originally referred to as "OHVs" by enthusiasts of the time and in Harley's official literature; the nickname arose from the California chopper culture of the late 1960s.
A retronym is a newer name for an existing thing that differentiates the original form or version from a more recent one. It is thus a word created to differentiate between two types, whereas previously no clarification was required.
Harley-Davidson, Inc. (H-D), or Harley, is an American motorcycle manufacturer, founded in Milwaukee, Wisconsin in 1903.
A motorcycle, often called a bike, motorbike, or cycle, is a two- or three-wheeled motor vehicle. Motorcycle design varies greatly to suit a range of different purposes: long distance travel, commuting, cruising, sport including racing, and off-road riding. Motorcycling is riding a motorcycle and related social activity such as joining a motorcycle club and attending motorcycle rallies.
As the design of Harley-Davidson engines has evolved through the years, the distinctive shape of the valve covers has allowed Harley enthusiasts to classify an engine simply by looking at the shape of the cover. The knucklehead engine valve covers have contours resembling knuckles on a person's fist that give the knucklehead its name.
A flathead engine, otherwise sidevalve engine, is an internal combustion engine with its poppet valves contained within the engine block, instead of in the cylinder head, as in an overhead valve engine.
The panhead is an ohv Harley-Davidson motorcycle engine, so nicknamed because the rocker covers resembled cooking pans. The engine is a two-cylinder, two-valve-per-cylinder, pushrod V-twin, made in both 61 c.i. (EL) and 74 c.i. displacements. The Panhead engine replaced the Knucklehead engine in 1948 and was manufactured until 1965 when it was replaced by the Shovelhead.
A motorcycle engine is an engine that powers a motorcycle. Motorcycle engines are typically two-stroke or four-stroke internal combustion engines, but other engine types, such as Wankels and electric motors, have been used.
The Harley-Davidson Sportster is a line of motorcycles produced continuously since 1957 by Harley-Davidson. Sportster models are designated in Harley-Davidson's product code by beginning with "XL". In 1952, the predecessors to the Sportster, the Model K Sport and Sport Solo motorcycles, were introduced. These models K, KK, KH, and KHK of 1952 to 1956 had a sidevalve engine, whereas the later XL Sportster models use an overhead valve engine. The first Sportster in 1957 had many of the same details of the KH including the frame, fenders, large gas tank and front suspension.
The intake/inlet over exhaust, or "IOE" engine, known in the US as F-head, is a four-stroke internal combustion engine whose valvetrain comprises OHV inlet valves within the cylinder head and exhaust side-valves within the engine block.
The Evolution engine is an air-cooled, 45-degree, V-twin engine manufactured from 1984 by Harley-Davidson for the company's motorcycles. It was made in the 1,340 cc (82 cu in) displacement for Harley-Davidson Big V-twins bikes, replacing the Shovelhead engine until 2000 when the last EVO was placed in a production factory custom FXR4. In 1999, it was replaced by the Harley-Davidson Twin Cam 88 in the Touring and Dyna model and in 2000 in the Softail models. Also available in the Sportster model beginning in 1986, it was made in the 1,100 cc (67 cu in) displacement until 1988 and is still made in the 883 cc (53.9 cu in) and 1,200 cc (73 cu in) displacements for the Harley-Davidson Sportster, replacing the ironhead Sportster engine.
The Harley-Davidson Twin Cam engines are motorcycle engines made by Harley-Davidson since 1998. Although these engines differed significantly from the Evolution engine, which in turn was derived from the series of single camshaft, overhead valve motors that were first released in 1936, they share a number of characteristics with nearly all previous Harley-Davidson engines. Both engines have two cylinders in a V-twin configuration at 45°, are air-cooled, and activate valves with push-rods. The crankshafts have a single pin with a knife and fork arrangement for the connecting rods. These are sandwiched between a pair of flywheels.
The Harley-Davidson FL is a model designation used on Harley-Davidson motorcycles since 1941. The FL prefix is mostly applied to Harley-Davidson's large-framed bikes, including the current Touring series, and also the Softail series, especially those with traditional styling, 16-inch front wheels, and either Springer forks or large-diameter telescopic front forks.
The Harley-Davidson XA was a flat-twin, shaft drive motorcycle made by Harley-Davidson for the US Army during World War II.
The Indian 841 was a motorcycle designed by the Indian Motocycle Manufacturing Co. for desert warfare. It pioneered the drivetrain configuration later popularized by Moto Guzzi, having a longitudinally mounted air-cooled 90-degree V-twin with shaft drive to the rear wheel.
Rikuo Internal Combustion Company 陸王 was one of the first motorcycle manufacturing companies in Japan. In the early 1930s Rikuo operated under the license and name of Harley-Davidson, using their tooling, and later under the name Rikuo until 1958. Harley-Davidson themselves did not publicize this Japanese connection because the Japanese were helped in developing mass-production techniques by the introduction of this factory into Japan just prior to the Second World War. The Society of Automotive Engineers of Japan (in Japanese) rates the 1935 Rikuoh Large Motorcycle as one of their 240 Landmarks of Japanese Automotive Technology.
S&S Cycle is an American motorcycle engine and parts engineer and manufacturer. The company was founded in 1958 by George J. Smith and Stanley Stankos in Blue Island, Illinois. The company started by selling high performance pushrods for Harley-Davidson motorcycles, and today they still make parts for a variety of V-Twin bikes. The company's current president is Paul Langley.
The ironhead was a Harley-Davidson motorcycle engine, so named because of the composition of the cylinder heads. The engine is a two-cylinder, two valves per cylinder, pushrod V-twin. It was produced from 1957 until 1985 and was replaced by the Evolution engine in 1986.
The Cleveland Motorcycle Manufacturing Company, sometimes called Cleveland Motorcycle, was a motorcycle manufacturer in Cleveland, Ohio from 1902 to 1905 and again from 1915 to 1929.
The Harley-Davidson Model W, also known as the Sport Twin, is a motorcycle made by Harley-Davidson from 1919 to 1923. Unusually for a Harley-Davidson motorcycle, the Model W had a flat-twin engine and a trailing link fork. The Model W set speed records on runs from New York City to Chicago and from the Canada–United States border to the Mexico–United States border. Slow home market sales led to the end of production after four years.
The Harley-Davidson 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 2017. 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 models, where the engine was rigidly mounted.
Harley and the Davidsons is a 2016 American television miniseries directed by Ciarán Donnelly and Stephen Kay, and co-written by Nick Schenk, Evan Wright and Seth Fisher which dramatizes the origins of motorcycle manufacturer Harley-Davidson, and how Arthur Davidson founded the company together with his brothers Walter Davidson, Sr. and William A. Davidson, along with their childhood friend William S. Harley.
The Harley-Davidson Fat Boy, is a popular V-twin softail cruiser motorcycle with solid-cast disc wheels.. Designed by Willie G. Davidson and Louie Netz, Harley-Davidson built a prototype Fat Boy in Milwaukee for the Daytona Bike Week rally at Daytona Beach in 1988 and 1989. Fat Boys produced from 1990-2017 are coded FLSTF, and FLFB from 2018.
Flathead motorcycles are a type of bike that was a standard for pre-war motorcycles, in particular US V-twins such as Harley-Davidson and Indian, some British singles, BMW flat twins and Russian copies thereof.