Bicyclette à moteur auxiliaire MONET GOYON Type M21

The Motorox is a small 34 cc auxiliary engine, produced by Monet & Goyon after World War II.

It is a single-cylinder 2-stroke engine with a horizontal design, delivering approximately 0.6 hp at 5,500 rpm.
Ignition is provided by a magneto.

It was sold as a kit to be mounted on a bicycle, with a clutch operated by tilting the engine, a 2 L fuel-mix tank, and pedal control. The advertised top speed is very modest: between 15 and 20 km/h, depending on sources.
Its weight is around 7.2 kg, making it quite light for an auxiliary engine of the time.

The Motorox suffered from reliability issues: it was considered underpowered and fragile, which limited its distribution.

 

  • Horizontal 2-stroke engine, 34 cc
  • Magneto ignition
  • Manual clutch
  • Transmission via internal gear in the pedal crankset