Single cylinder engines (known as "singles" or occasionally "thumpers") may have the cylinder
 vertical or horizontal, the latter particularly common in step-through or underbone
 motorcycles. Single cylinder engines require a larger flywheel, hindering ultimate
 performance but are a lot easier to maintain in almost every respect. In road motorcycles,
 single-cylinders tend to be associated with cheaper, utility motorcycles for daily transport.
 These motorcycle engines are tuned to give more power at lower engine revolutions,
improving control, safety and engine longevity.

The need for the flywheel effect is less pronounced in all forms of
 competition motorcycles since they spend almost no time at tick-over speeds,
all through the 1950s many of the fastest road racing motorcycles such as the
Manx Norton were single-cylindered. The reduced weight and narrow width of
 single-cylinder motorcycles continue to make the layout well suited for the great
 majority of off road motorcycles, including those in top competition.

Split Single (a radical form of two-stroke) were used very successfully
 by DKW and Puch between and after the wars, losing out only to the loop-scavenging
 Japanese twin and triple machines of the