Yeah you do have the CH engines which were a 125cc, you also have the CN engines which are liquid cooled and 200 or 250cc. Not really sure on the CN as I aint played with them. Anyways they all share some design, the GY and CH are closer to brother and sister while the CN is a cousin.
You have to be careful with the GY6 and all of it's clones. You have short cases and long cases and everybody that knocked it off seemed to change something so all gy6 parts are not universal, A blocks, B blocks, egr and non egr heads, and so on. Best place to learn about them is over on a honda ruckus form.
I have a 150 in a 300lb 2 seat buggy that is actually pretty impressive for what it is. I'm swapping it out for a 400cc atv engine and plan on taking the 150 and trying to fit it in something like a baja mini bike. If I only rode around in our pasture on 20 inch tires it would be great but in the woods and mud I need more tire and the 150 can't do anything bigger than a 22 without putting excess strain on it. a 300cc would be perfect but I have the 400 on an old 4 wheeler that runs but I can't find parts for the bike.
