As per CVC 5030, Motorized bicycles do require a "SPECIAL PLATE"In california. DMV does not consider this a regular registration, SO, there is a code that says registration is not required for motorized bicycles, And a regular registration is not required, BUT a "SPECIAL PLATE" IS required. Yeah, it can get confusing. But, heres the law in California.
Of course I'm assuming motorized bicycle laws are pretty close to the same all over. Most places that are OK with MB's kinda tend to make the same laws. I suggest you go to YOUR DMV website and do a search on Motorized Bicycle. I bet yer gonna find a lot of stuff the Cops dont even know about
Yer also required to have a M-1 or M-2 license here. Good thing the cops dont really know the laws, because I've NEVER had a bike license of any kind.
Most times I was pulled over the cop just wanted to check out the cool bike. Once in a while ya get a idiot cop that wants to just find a reason to give you a ticket. Headlight, tail light AND brake light, mirrors AND dont get caught doing over 30mph and you'll be fine. I made a cop turn purple one day trying to give me a ticket. He finally gave up and walked off muttering to himself. I wished him a pleasant day, which seemed to make him even madder for some reason.LOL Sometimes ya gotta be the teacher, Even with cops, Just do it with a smile and be polite.