|The Evolution Of The Engine
The first engine that William Harley ever designed was in
1901, before the Harley Davidson Company even began. It was a
small engine that displaced 7.07 cubic inches and had 4-inch
flywheels. This engine was designed to power a regular
bicycle, however it did not give the bike enough power to
ascend the hills of Milwaukee.
The next engine Harley developed with the assistance of the
Davidson brothers was bigger and more powerful. This engine
was 24.74 cubic inches with 9-3/4 inch flywheels weighing 28
pounds. The group also received help with this engine from
outboard motor pioneer Ole Evinrude, and was much more
successful, premiering the first Harley Davidson motorcycle in
1904 at a race in Milwaukee.
Since then Harley Davidson has continued to improve and
develop their motorcycle engines. The Flathead engine was
manufactured between 1929 and 1974. These engines did not have
overhead valves. The valves ran alongside the engine and
opened upward into a chamber beside the combustion chamber. A
typical flathead engine displaced about 45 cubic inches and
produced about 22 horsepower.
The Knucklehead engine was manufactured between 1936 and 1947.
This engine was available in 60 cubic inch and 74 cubic inch
variations, producing 40 to 45 horsepower.
The Panhead engine was manufactured between 1948 and 1965.
This engine also came in 60 cubic inch and 74 cubic inch
variations, but produced 50 to 55 horsepower. The biggest
difference between the two engines was the aluminum heads on
the panhead and internal oil lines, as opposed to external oil
lines on the knucklehead.
The Shovelhead engine was manufactured between 1966 and 1985.
This engine displaced 74 cubic inches and produced 60
The Evolution engine was manufactured between 1984 and 1999.
This engine displaced 81.8 cubic inches and produced 70
horsepower. Some smaller evolution engines are still produced
today, and are used in the Sportster line of Harley Davidson
The Twin Cam 88 engine began to be manufactured in 1999. This
engine got its name because it has 2 cams in the crankcase to
activate the valves. This engine displaces 88 cubic inches and
produces 80 horsepower making it the largest production Harley
Davidson engine. This engine is air-cooled and uses overhead
valves activated by pushrods.
The Revolution engine began to be manufactured in 2001. This
engine is currently only used in the VSRC model. This engine
is quite different from the others produced by Harley
Davidson. It is water-cooled instead of air-cooled. Its V
angle is 60 degrees instead of 45 degrees. It has 4 overhead
cams instead of two in the crankcase and it is fuel injected.
This engine s smaller at 69 cubic inches, but it produces 115
horsepower due to its much shorter stroke.
Harley engines are big. They have a very distinctive sound.
Once you know what a Harley sounds like you will always
recognize when one is coming. The Harley sound is part of the
whole Harley experience. The sound is enhanced by removing the
muffler and comes from the way the engine is designed.