Factory Fat - Harley-Davidson V-Twin Motor history.

	Harleys first v-twin 1909-1911 45-degree 49.5 cubic w/ 7hp

	F-head: 1911-1929

	Flathead: 1929-1936 The Flathead was named because of the telltale flat vented tops that are recognizable at the top of each cylinder head. 45cu The engine proves to be so reliable that variations of it are available on Harley-Davidson motorcycles as late as 1973. (pictured is a 45" "R" 1932-36)
	knucklehead: 1936-1947 On the eve of WW2, Harley-Davidson^® introduced an overhead- valve V-twin® with "knuckly" covers on the valves. Overhead valve EL-61cu 40hp Side valve-80cu
	Panhead: 1948-1965 New features are added to the 61 and 74 overhead valve engines, including aluminum heads and hydraulic valve lifters that supplied oil through rocker arms, the panhead hit the market in 1948, named for the pan-like cover where the knuckles used to be.

	1956 KHK K-Series 1952-53 K 45" 750cc. 1956-56 KH 54" 885cc

	1957 Ironhead The motorcycling public met a new motorcycle called the Sportster®. It premiers as a 55 cubic inch overhead valve engine. 1959 XLCH Sportster Engine

	Shovelhead: 1966-1985 By 1966 the Panhead underwent still more improvements, the most noticeable being the distinctive enclosed cylinder head in a sleek, slightly curved top. At a glance this looks unmistakably like a shovel with the pushrods resembling the handle of a shovel, and the head, the shovel itself.

	Evolution: 1984-1999 In 1984 on the heels of a bold employee buyout of AMF, The motor company went public and introduced it's now famous redesign of the v-twin. This radical new design utilized styled square blocks to house the valves. 4-Cycle, 45 Degree V-Type, 1340cc, 80cu compression: 8.5:1, Oil-bath diaphragm clutch and electronic ignition.

	1986 The Sportster® motorcycle line receives the Evolution V-twin engine. 1986 - 883cc & 1100cc 1988 - 883cc & 1200cc

	Twin Cam 88^TM: 1999-2006 & Twin Cam 88B^TM 2000-2006 With numerous American motorcycle manufacturers trying to surface and re-surface Harley-Davidson introduces it's most revolutionary engine yet. The Twin Cam 88^TM gets its name from its two cams. B= Balanced 1450cc

	Revolution^TM: 2001-present Liquid-cooled, 1130cc, 115 horsepower. The Revolution engine's basic configuration is a 60° V-Twin with dual overhead cams and four-valve heads. It's a high-revving design, with a 9000 rpm redline. Two velocity stacks housed in a massive air box allows it to breathe aggressively. Electronic fuel injection system, modified for high performance, and a new high-energy plug-top ignition coils.

	Twin Cam 96 2007-Present Compression 9:2:1 EFI

1st side-valve motor: 1926 - single cylinder.
1st side-valve twin: 1929 45" "D"
Side-valve motors made until 1973.
Racing H-Ds of the '20s were the "JD", "JDH" etc. single & twin-cam 1000 & 1200 cc IOE, and "pea-shooter" (21" 350cc OHV single), not side-valve. 1st successful racing side-valve was the mid-1930s RLDR 45".