Chicago Moped Store Is It Legal Or Illegal To Ride In A Scooter/moped In Chicago, Illinois?

Is it legal or illegal to ride in a scooter/moped in chicago, Illinois? - chicago moped store

I recently purchased X-Treme XG-550 (kerosene) in Illinois. I live in the Chicago area. I have tried in the park to see if it works. I ran well and be loved. The only problem is that after a certain time in the park to be a policeman stopped me and told me he could not with the scooter / bike in the park, it runs on 50CC gasoline engine. I'm 25 30 miles per hour, I knew it was not necessary to register it as a car and insurance services. I'm confused, there is a law that prevents me from using this scooter? Was I breaking the law if I do I can in the park or anywhere else, I use? Is it illegal in Chicago, Illinois, one of these things?