Hey there at around 4pm this afternoon I received my from zoombicycles! ( 2days shipping!!!). Unfortunately with all my excitement I mounted the engine, but forgot to put some rubber underneath the motor mounts. And had a couple questions; has anyone ever had any problem with the motor mounts for the over sized tube vibrating holes in the frame and/or cracking the frame? and how much clearance between is needed between the sprocket and the frame?