Gas scooters and NO registration/insurance?

What country of the world? In the USA it varies by state, but in most states only mopeds are street legal, and for some dumb reason that means they have to have a set of pedals. So scoots are all illegal, unless they are sporting a set of pedals and a drive linkage, like a chain to the rear wheel. This usually goes for both gas or electric types of scooters. Larger stuff is classed as motorcycle and needs all the leagal paperwork, titles, registration, insurance etc.

I think dogman might be overstating things. Generally, any gas scooter with 50cc engine or under (or equivalent) is not considered a motorcycle, and therefore doesn't require a motorcycle license, registration, and insurance. That means that most of the small scooters fall into a category for moped, scooter, or motor-driven bicycle. While the laws for these most definitely vary by state, I think small scooters without pedals are legal to ride in the majority of states.

What state are you in? These rules vary a LOT by state.

In Michigan you can ride a moped without registration or insurance - but you do need a valid drivers license. There is also provision to allow a 15 year old to ride one with a special restricted license. No helmet is required if you're over 21 (apparently they think your head is hard enough at that point!).

In Michigan a moped is defined as a two wheel vehicle that has a maximum speed of 30 mph on level ground, no more than 2HP and for a gas bike no more than 50cc displacement. It doesn't have to have pedals.