Drive unit for a two-wheeled motor-driven vehicle and vehicle including said unit

A two-wheeled motor-driven vehicle comprising a drive unit, said unit comprising an assembly comprising a motor and a gearing down relay, suspension arms connected to the motor and receiving, in the vicinity of free ends of the arms, a driving wheel of the vehicle, support means for a suspended part of the vehicle, the motor having a crankshaft, the relay having an output shaft and an input shaft, the input shaft being drivingly connected to the crankshaft of the motor and being spaced further away from the crankshaft than the output shaft of the relay, a pedal crank gear having a shaft which is located in said assembly between the motor and the relay and a unidirectional coupling drivingly coupling the crank gear shaft to the output shaft, said unit being mounted on the vehicle to pivot about a transverse axis under the suspended part of the vehicle and being connected, at the rear part thereof, to the support means for said suspended part.