Oklahoma

Motorcycle:

“any motor vehicle having: 1. A seat or saddle for the use of each rider; 2. Not more than three wheels in contact with the ground, but excluding a tractor; and 3. A combustion engine with a piston or rotor displacement of one hundred fifty cubic centimeters (150 cu cm) or greater.”

Motor-Driven Cycle:

“any motor vehicle having: 1. A power source that: a. if the power source is a combustion engine, has a piston or rotor displacement of greater than thirty five cubic centimeters (35 cu cm) but less than one hundred fifty cubic centimeters (150 cu cm) regardless of the number of chambers in the power source, b. if the power source is electric, has a power output of greater than
one thousand (1,000) watts; and 2. A seat or saddle for the use of each rider; and 3. Not more than three wheels in contact with the ground.”

Moped:

“any motor-driven cycle with a motor which produces not to exceed two brake horsepower and which is not capable of propelling the vehicle at a speed in excess of thirty-five (35) miles per hour on level ground. If an internal combustion engine is used, the displacement shall not exceed fifty (50) cubic centimeters, and the moped shall have a power drive system that functions directly or automatically without clutching or shifting by the operator after the drive system is engaged.”