A single-cylinder engine is a basic piston engine

Reciprocating engine

A reciprocating engine, also often known as a piston engine, is a heat engine that uses one or more reciprocating pistons to convert pressure into a rotating motion. This article describes the common features of all types...

 configuration of an internal combustion engine

Internal combustion engine

The internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine, the expansion of the high-temperature and high -pressure gases produced by combustion apply direct force to some component of the engine...

. It is often seen on motorcycle

Motorcycle

A motorcycle is a single-track, two-wheeled motor vehicle. Motorcycles vary considerably depending on the task for which they are designed, such as long distance travel, navigating congested urban traffic, cruising, sport and racing, or off-road conditions.Motorcycles are one of the most...

s, auto rickshaw

Auto rickshaw

An auto rickshaw or three-wheeler is a usually three-wheeled cabin cycle for private use and as a vehicle for hire. It is a motorized version of the traditional pulled rickshaw or cycle rickshaw...

s, motor scooters, moped

Moped

Mopeds are a type of low-powered motorcycle designed to provide economical and relatively safe transport with minimal licensing requirements.Mopeds were once all equipped with bicycle-like pedals , but moped has been increasingly applied by governments to vehicles without pedals, based on their...

s, dirt bikes, go-kart

Go-kart

thumb|A [[Kart racing|racing kart]] at the [[Commission Internationale de Karting|CIK-FIA]] European Championship 2008A go-kart is a small four-wheeled vehicle...

s, radio-controlled model

Radio-controlled model

A radio-controlled model is a model that is steerable with the use of radio control. All types of vehicles imaginable have had RC systems installed in them, including cars, boats, planes, and even helicopters and scale railway locomotives....

s and has many uses in portable tools and garden machinery

Garden tool

A garden tool is any one of many tools made for gardens and gardening and overlaps with the range of tools made for agriculture and horticulture...

. It has been used in cars

Automobile

An automobile, autocar, motor car or car is a wheeled motor vehicle used for transporting passengers, which also carries its own engine or motor...

 and tractor

Tractor

A tractor is a vehicle specifically designed to deliver a high tractive effort at slow speeds, for the purposes of hauling a trailer or machinery used in agriculture or construction...

s.
Single-cylinder engines are simple and compact, and will often deliver the maximum power

Power (physics)

In physics, power is the rate at which energy is transferred, used, or transformed. For example, the rate at which a light bulb transforms electrical energy into heat and light is measured in watts—the more wattage, the more power, or equivalently the more electrical energy is used per unit...

 possible within a given envelope. Cooling is simpler than with multiple cylinders, potentially saving further weight, especially if air-cooling can be used.

Single-cylinder engines require more flywheel effect than multi-cylinder engines, and the rotating mass is relatively large, restricting acceleration and sharp changes of speed.