The first motorcycles were powered by steam engines.
 The earliest example is the French Michaux-Perreaux steam
velocipede of 1868. This was followed by the American Roper
 steam velocipede of 1869, and a number of other steam powered two
 and three wheelers, manufactured and sold to the public on through
the early 20th century.

Using frames based both on the earlier boneshaker
 and the later—and in many ways completely modern—safety
bicycle design, these early steam motorcycles experimented
with a variety of engine placement strategies, as well as
transmission and options. While today nearly every motorcycle
 has its engine in the center of the frame, this became standard
only around 1900-1910[verification needed] after nearly
every possible engine location was tried.
 The modern scooter engine arrangement was arrived at
in the 1940s[verification needed] and remains the same today.

The Otto cycle gasoline internal combustion
engine was first used on an experimental two wheeler
created by Gottlieb Daimler to test the practicality of
 such an engine in a vehicle. This motorcycle, the Daimler Reitwagen,
is credited as the world's first motorcycle by many authorities,
 partially on the assumption that a motorcycle is defined not as
any two wheel motor vehicle, but a two wheel internal combustion
engine motor vehicle.[1] The Oxford English Dictionary, for example,
 defines the word motorcycle this way.[2][3] The steam
cycles were also simply neglected and forgotten by many
 historians, even as the Michaux-Perreaux waited
forty years[verification needed] on display in the National
 Motor Museum, Beaulieu.(verification needed)

In recent years, a surge in interest in clean energy has
put many new electric powered two wheelers on the
market, and they are registered as motorcycles or scooters,
 without the type of powerplant being an issue.
 Diesel motorcycles were also been experimented with briefly
throughout the 20th century, and are again the subject of
interest due to fuel economy and the needs of military logistics
. The USMC has ordered a new diesel motorcycle, the M1030 M1,
that can use the same fuel, JP-8, as the rest of their armored
 vehicles, aircraft, cars and trucks.

The overwhelming majority of the motorcycles produced
and used in the world today have small displacement
air-cooled single-cylinder engines, both two- and four-strokes.
[citation needed] In the wealthier parts of the world,
 Europe and Japan, larger displacements and multiple cylinders are
 common alongside small-displacement bikes required by various
licensing and rider experience requirements, and so a very diverse
range of sizes, cylinder numbers, configurations, and cooling
systems are seen on the road. Many developed countries
have graduated licensing, where a rider is licensed for a period
of time to ride only smaller-displacement motorcycles before
being allowed to ride larger ones. In the United States, there
are no such mandates, and so the mix is skewed even further to
the largest displacements, consumer demand drives manufacturers
 to offer their largest motorcycles to that country,
and to export far fewer sub-600 cc (37 cu in) models
to the American market