Be on the forum for a while and you'll quickly discover some places self-built motorized bicycles aren't legal at all for use on the public roadways and it's strictly enforced. Other places they may not be legal but the police tend not to bother you as long as you obey the traffic laws.
Some places self-built motorized bicycles are legal but they also strictly enforce their guidelines. Other places where they are legal the guidelines may not be strictly enforced as long as you obey the traffic laws. It's primarily about where you live and secondarily about how you drive
And then you have the best of all laws in the country like what I have here in New Mexico regarding motorised bikes:
Chapter 18 – Other “Vehicles”
Section E. Motorized Bicycles
Revised November 30, 2017
Motorized Bicycles are
NOT considered to be mopeds or motorcycles.
By current MVD practice,
motorized bicycles are considered to be bicycles (not mopeds or motorcycles) and are not subject to the titling and registration requirements of the Motor Vehicle Code.
You only have to adhere to rules of the road riding a bicycle here in New Mexico as this statute spells out.
Section D. Bicycles
Revised November 30, 2017
Bicycle defined (§66-1-4.2(A))
A bicycle is a device propelled by human power upon which any person may ride, having two tandem wheels, except scooters and similar devices.
Traffic laws apply to bicycles (§66-3-702)
Every person riding a bicycle upon a roadway shall be granted all of the rights and shall be subject to all of the duties applicable to the driver of a vehicle, except as noted below.
Ridng bicycles on roads or bicycle paths (§66-3-705)
1. Every person operating a bicycle upon a roadway shall ride as near to the right side of the roadway as practicable, exercising due care when passing a standing vehicle or one proceeding in the same direction.
2. Persons riding bicycles upon a roadway shall not ride more than two abreast except on paths or parts of roadways set aside for the exclusive use of bicycles.
3. Notwithstanding any provision of this section, no bicycle shall be operated on any roadway in a manner that would create a public safety hazard.
??Lamps and other equipment (§66-3-707)
1. Every bicycle when in use at nighttime shall be equipped with a lamp on the front which shall emit a white light visible from a distance of at least five hundred feet to the front and with a red reflector on the rear of a type approved by the division which shall be visible from all distances from fifty feet to three hundred feet to the rear when directly in front of lawful upper beams of head lamps on a motor vehicle. A lamp emitting a red light visible from a distance of five hundred feet to the rear may be used in addition to the red reflector.
2. No person shall operate a bicycle unless it is equipped with a bell or other device capable of giving a signal audible for a distance of at least one hundred feet, except that a bicycle shall not be equipped with, nor shall any person use upon a bicycle any siren or whistle.
3. Every bicycle shall be equipped with a brake which will enable the operator to make the brake wheels skid on dry, level, clean pavement.
The Motor Vehicle Division is neither required nor authorized to title or register bicycles.