California Vehicle Code definition of
Motorcycle
CVC Section 400. (a) A "motorcycle" is any motor vehicle having a seat or
saddle for the use of the rider, designed to travel on not more than
three wheels in contact with the ground, and weighing less than 1,500
pounds.
(b) A motor vehicle that has four wheels in contact with the
ground, two of which are a functional part of a sidecar, is a
motorcycle if the vehicle otherwise comes within the definition of
subdivision (a).
(c) A motor vehicle that is electrically powered, has a maximum
speed of 45 miles per hour, and weighs less than 2,500 pounds, is a
motorcycle if the vehicle otherwise comes within the definition of
subdivision (a).
(d) A farm tractor is not a motorcycle.
(e) A three-wheeled motor vehicle that otherwise meets the
requirements of subdivision (a), has a partially or completely
enclosed seating area for the driver and passenger, is used by local
public agencies for the enforcement of parking control provisions,
and is operated at slow speeds on public streets, is not a
motorcycle. However, a motor vehicle described in this subdivision
shall comply with the applicable sections of this code imposing
equipment installation requirements on motorcycles.