Like their four-wheeled cousins, electric motorcycles are often described as automatic vehicles. This is actually inaccurate. Most electric bikes technically have a single drive ratio, so there aren’t multiple gears to be shifting ‘manually’ or ‘automatically’ between.
All vehicles have some form of transmission – automatic, manual, variable, or other – which refers to the components that transmit power from the motor to the wheel. These transmissions generally include a variety of gears, which provide different ratios between input and output, and a clutch, which is controlled by the operator in a manual vehicle, or a vehicle control module in an automatic.
Gearboxes are necessary because of the wide operating requirements of a vehicle compared to the narrow operating window of an internal combustion engine (ICE). However, electric vehicles are able to do away with gearboxes because the meaningful operating range of the electric motor tends to be far broader. They’re also able to do away with the clutch, because in an electric motor, you can produce a great deal of torque at low or even 0 RPM.
In the case of a typical ICE motorcycle, you have a clutch controlled by a hand lever that engages the motor with the gearbox. The gearbox is controlled by a foot lever with gears selected according to what you’re doing (e.g. accelerating hard or cruising down the highway). The gearbox is then connected to a sprocket which drives a chain, which in turn transmits power to the rear wheel. In the case of the C-Series, there’s no need for a clutch, because we can produce enough torque at 0 RPM to propel the vehicle, and there is also no need for a gearbox, as we’re able to produce this constant, blistering amount of torque up until about 4000 RPM. The only remaining piece of the puzzle is the typical chain-and-sprocket combo, which in our case has been opted out for a stronger, lower maintenance belt and pulley.
So, in summary, the C-Series transmission is a single/fixed-ratio synchronous belt-and-pulley system. Not strictly an automatic.