Christopher Middleton

I was given a "Go-Kart" its an old Carter brothers dlx150 but the engine is not the same that came with this Kart. I am trying to ID it so i can look at getting some parts for it. the pictures attached are of the motor and the only ID marks on it. I am thinking its some sort of 200cc from the 1980's does anyone have a better Idea? I am really trying to get a rebuild kit for the carburetor. on the carburetor is Keihin 63 AA YKT