A single-cylinder engine, sometimes called a thumper, is a piston engine with one cylinder. This engine is often used for motorcycles, motor scooters, go-karts, all-terrain vehicles, radio-controlled vehicles, power tools and garden machinery. Single-cylinder engines are made both as 4-strokes and 2-strokes.

Bond Minicar is a series of economical three-wheeled microcars which were manufactured by the British car manufacturer Sharp's Commercials Ltd, in Preston, Lancashire, between 1949 and 1966.