Welcome to the forum. Like Ale said do lots of research here before you actually get the ball rolling. There are places on the Forum ad board that should point you towards a rear mount system. There have been members that have pulled off squeezing a predator 212cc in the frame. I don't want to take away from your idea, but for a motor that big on a rear mount is just asking for trouble. Don't plan on taking it racing! Your center of gravity will be non-existent because the center mass will be so top heavy (you & motor) and it may have the tendency to top-side. I recommend getting all the information that you need pertaining to the 212cc and put it inside the frame rather then on a rear rack. Either way, it's always good to get some more newbies joining the forum. When you get started be sure to take plenty of pictures for all of us.