legality

I'm looking for MA approved engines / motorized bicycles. Currently, I'm trying to figure out if https://www.bicycle-engines.com/49cc-4g-t-belt-drive-complete-gas-powered-engine-kit/ will work. I'm confused by the big Non-Road Engine sticker on it. Also, I'm not sure how to reduce the top speed...

Hey everyone, I'm new to this forum so I'll give a quick introduction: I'm Mike, I'm 15 (finally old enough to legally use a mb) and I live in central NJ. I have always had a passion for motors, building, and biking, so the thought of being able to make a mb sounds like a fantastic idea to me. I...