If you are a chopper lover then
you are probably familiar with the
v-twin engine. Do you know why the
V Twin is named a V Twin?
The V Twin engine is a
two-cylinder engine layout in
which the cylinders form a
"V". The V-Twin engine's
pistons are aligned so that, if
viewed along the line of the
crankshaft, they appear to be in a
The V configuration reduces the
overall engine length and weight
compared to an equivalent straight
engine (the straight engine or
in-line engine is an
internal-combustion engine with
all cylinders aligned in one row.)
configuration allows for optimum
torque for a given
V twin engines can
be mounted in the transversal
position (the definition of
'transversal' is a line extending
or lying across at right angles to
the long axis.)
V twins on Harley
Davidson Motorcycles are mounted
in a parallel position.
The longitudinal V
Twin (the definition of
longitudinal is: lengthways,
lengthwise) as seen on Moto-Guzzis
and some Hondas is less common. This
position is well adapted to its
transmission shafting, but has the
disadvantage of causing a torque
reaction that tends to lean the
motorcycle on the side.
The first V
Twin was introduced in 1903,
updated with two and three-speed
The Indian was one of the first
US makers to offer a successful V
Twin in 1907.
The most obvious
configuration for a V Twin is a 90°
angle, but other angles can be
achieved like the 45°
Here's how a V Twin engine
A normal two
cylinder engine fires the pistons
in such a way that one fires on
the first revolution of the
crankshaft, and the second one
first on the second revolution.
The engines runs
quite smooth under this design.
But a Harley
engine has two pistons, and the
crankshaft has only one pin (in
the design above, which is a
common design, there are two crank
pins for the connecting rods which
the pistons connect to), and both
pistons are connected to it.
So the pistons
fire almost at the same time.
Whereas in the example above they
fire at different intervals.
This gives the
choppers, and most particularly
the Harley Davidson V-twin its
unique sound, throaty, in your
gut...you know what I mean...
motorcycle is one of the early
versions at 90 degrees...
As you probably know, the first
choppers to come out with this
engine were the Harleys, so we can
easily say that the v-twin engine
was born in the Harley Davidson's
The Harley V Twin
is generally credited to Bill
Harley, who designed it in 1908 as
H-D's Chief Engineer. He went to
work on the design right after
graduating from the University of
Wisconsin in 1908. Those first
Harley V-twin engines proved to be
a failure. In 1910, the V-twin
engine dropped from Harley
But it was soon
re-designed and appeared again in
V-tiwn's are not
just for Harley's and Indian's.
Many manufacturers use the
configuration on their bikes:
Suzuki, Kawasaki, Yamaha,
Honda...all have V-twins.