To give you an idea, most four stroke 250cc twins or 350cc singles would come the below 33 BHP limit, two strokes of the same size would probably be over the limit. These are rough guide lines and you will need to check with the manufacturer to be sure.

It is possible to fit power restrictor kits to larger machines to bring them down to 33 BHP, but to be honest there may not be a lot of point in doing this unless it suits your circumstances.