Montana, a motorized bicycle must meet the following requirements:
- 2 or 3 wheels.
- A maximum speed of 30mph on flat ground.
- A motor no larger than 50cc (no more than 2bhp).
- An automatic transmission
- Foot pedals to permit muscular propulsion
No license is required to ride a motorized bicycle in Montana as long a it meets the specifications above.
No registration is required to ride a motorized bicycle on public roads in Montana as long as it meets the specifications above.
If your motorized bicycle is exceeds the specifications then it must be registered as a motorcycle and you will need a motorcycle license.