Yes it has a motor box. There is 4 1/2 inches of room for you to mount in. From the back of the carb to the nearest conflict, which is the mounting bolt for the rail there is 1 1/2 inches of room . This is were the carb is going to hit the bolt on the .82. The width should not be issue.
I dont have my small cylinder instructions to look up the dimensions at the moment.

Also consider a different engine mount, mine will flex pretty good.