Sure anyone can get a moped or whatever, but that isn't the point of a motor bicycle. It's just a fun hobby and it's much cooler to motorize a bike....it's fun.

Google about it....a lot of people come up with neat ideas...and bikes.

The cheap 2 stroke china engines really suck sometimes...it's a crap shoot....might get one with a pretty good crank balance....might not. I usually rip them apart and have a machinist balance the crank and I slide in Japanese bearings....as well as porting the head and taking care of any metal flash the factory should of done.
With a balanced crank, better bearings and some basic machining...these engines will do for a long time, but they are a tinker toy.... I wouldn't get one if yo uplan on commuting to work every morning.... or plan on being late 2 days out of 5.