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Harley-Davidson V-Twin Motor history.

Click on engine thumbnail for larger picture

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.


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.



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.




The Sportster® motorcycle line receives the Evolution V-twin engine.

1986 - 883cc & 1100cc
1988 - 883cc & 1200cc


Twin Cam 88TM: 1999-2006  & Twin Cam 88BTM  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 88TM gets its name from its two cams.

B= Balanced



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


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".

*Info from Harley-Davidson®



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