Is there a legal motorized vehicle in Washington for someone under 16?
Obviously much depends on your own State’s rules and regulations, but nationally, anything under 49cc has been designated as legal to operate without a license on the road, meaning those small scooters you see ( some of them, anyway ). You can put a small gas engine on your bicycle, it’s been done before, long as it’s a small one, you should have no legal trouble. Mopeds are legal in most States with no license, but some require them to have tags, others don’t. You need to contact your local police station and ask direct, if you want the straight scoop. Don’t be embarrassed to ask them, they’re not gonna arrest you for asking questions.