In New York, mopeds (limited-use motorcycles) must be registered. But mopeds here must also meet all safety standards (brake light, kill switch, reflectors, electric horn, etc) The only Solexes that meet those standards are the 1966-74 California 3800-S, 1975 4600 V2s, 1977-79 4600 V3s, the Hungarian S-3800s, and the Chinese S 4800s, and the only ones on the NYS DMV certified list are 1976 or newer Solexes. All other Solexes would be considered motorized bicycles, which are not legal to register or ride on public roads in New York State. Every State is different, and you must check the regulations for your State to determine if you have a moped or motorized bicycle. In some States, mopeds and motorized bicycles are considered the same thing. In my experience, in most States, Solexes meet the criteria for a moped, which is generally: can be powered by motor or pedals, automatic transmission, less than 50 cc, less than 1.5 - 2 HP.