You fist need to determine if Massachusetts defines your mode of transportation as a scooter or a motorcycle. You will likely need to contact the MA Registry of Motor Vehicles to seek clarification since the descriptions of both may not give enough information for you to decide what they categorize your vehicle as.
The motorcycle manual for Massachusetts gives a motorcycle definition as any motor vehicle having a seat or saddle for the rider that is designed to travel with no more than 3 wheels contacting the ground, including any bicycle with a motor or driving wheels attached.
Your vehicle could not be classified as a motorized bicycle because they cannot exceed 50 cubic centimeters. Motorized scooters however are defined as a 2-wheeled tandem or 3-wheeled device that has handlebars, is designed to be stood or sat upon and is powered by an electric or gas powered motor that is capable of propelling the device with or without human propulsion. Motorized scooters may not be operated at a speed greater than 20 mph.
Under MA law, if your vehicle falls into the scooter category, it is regulated by the Registrar of Motor Vehicles and you must have a valid license or permit to operate it. Anyone operating a motorized scooter is subject to the motor vehicle laws of MA but is not required to register the scooter.
If instead your vehicle is classified as a motorcycle, it will need to be registered and you will need to show proof of insurance that is equal to the Massachusetts' minimum limits of 20,000/40,000 for bodily injury and 5,000 for property damage.
For motorcycle insurance follow this link or call 1-800-936-0356.