Heres the law in regards to riding motorized bikes in california,got it off the chp web site.
What is a moped or motorized bicycle?
•There are two types of motorized bicycles, defined in the California Vehicle Code (VC) Sections 406(a) and 406(b).
•Section 406(a) VC refers to a moped or motorized bicycle as any two or three wheeled device having fully operative pedals for propulsion by human power, or having no pedals if powered solely by electrical energy, has an automatic transmission, and a motor which produces less than 2 gross brake horespower and is capable of propelling the device at a maximum speed of not more than 30 miles per hour on level ground.
•Section 406(b) VC refers to a motorized bicycle as a device that has fully operative pedals for propulsion by human power and has an electric motor that:
◦Has a power output of not more than 1,000 watts;
◦Is incapable of propelling the device at a speed of more than 20 miles per hour on level ground; and
◦Is incapable of further increasing the speed of the device when human power is used to propel the motorized bicycle faster than 20 miles per hour.
Helmet requirement
Motorcycles, Motor-Driven Cycles, Motorized Bicycles/Mopeds (Section 406(a) VC ) - A helmet meeting Federal Motor Vehicle Safety Standard 218, self-certified by the manufacturer and displaying a 'DOT' emblem must be worn by all riders of motocycles, motor-driven cycles, and motorized bicycles/mopends.
Motorized Scooters - A bicycle helmet meeting the standards of either the American Society for Testing and Materials (ASTM) or the United States Consumer Product Safety Commission (CPSC) must be worn to operate a motorized scooter.
Motorized Bicycles (Section 406(b) VC) - A bicycle helmet meeting the standards of either the American Society for Testing and Materials (ASTM) or the United States Consumer Product Safety Commission (SPSC) must be worn to operator a motorized bicycle.
What is a motorized skateboard or motorized scooter?
•Effective 1/1/2005, a motorized scooter is any two-wheeled device that has handlebars, has a floorboard that is designed to be stood upon when riding.
•May have a driver seat that does not interfer with the ability to stand and ride and may also be designed to be powered by human propulsion.
•Powered by electricity or other source.
Driver's License Requirements
Motorized scooter
Effective 1/1/2005, a Class C driver license or driver permit is required.
Motorcycle, motor-driven cycle, motorized bicycle/moped (Section 406(a) VC)
•Must obtain an M-1 or M-2 endorsement on a driver's license.
•M-1 allows the driver to operate a motorcycle, motor-driven cycle and moped
•M-2 allows for operation of a moped or motorized bicycle only.
•To obtain an M-1 or M-2 endorsement, the driver must:
◦Pass the appropriate written exam
◦Pass riding skills test (DMV will accept certificate of competence from an approved novice motorcyclist training program instead of skills test, such as the California Motorcyclist Safety Program).
◦If the individual is under 21 years of age, mandatory successful completion of a Basic Rider education course approved by the CHP is required, such as the Basic Rider course available through the California Motorcyclist Safety Program.
Motorized Bicycle (Section 406(b) VC)
•Driver's License not required but rider must be at least 16 years of age.
Instruction Permit Requirements
•Operator must be at least 15 1/2 years old
•Operator must pass automobile written exam
•Operator must pass appropriate endorsement requirements for an M-1 and M-2 endorsement
•Operator must have completed an approved automobile driver education course
Note: An operator with an instruction permit may not carry passengers, ride after dark or operate a motorcycle on the freeway.
Equipment Requirements
•Brakes, tires, rear view mirror and horn in good operating condition
•Multi-beam headlight for 1978 models and later to remain on at all times
•Tail light and license plate light
•Front and rear turn signals for 1973 and later models
•Passenger footrests allowing any passenger to place feet on them
Safety Clothing
•Helmet as mentioned above. If face shield is worn, it must be shatterproof
•Eyeglasses or other eye protection
•High-top boots or shoes, preferably with steel toe protection
•Gloves
•Snug clothing covering arms and legs
•Brightly colored clothing and reflectorized material after dark