Re: Rubber mounting 4-stroke??!!
It is advised by most of the best builders to not use rubber mounts on any of these bikes.
The bike might feel a little smoother, but all you're really doing is allowing the engine to shake harder in the frame & it will eventually break the mounting bolts.
The best way is to mount the engine hard to the frame as solidly as possible so the engine vibrations will be dispersed through the frame.