You'll need a new airbox base plate, and the rubber engine flap.
Also as mentioned above, get a look inside the carbs to see what you are running

How is it restricted, inserts in the carb rubbers?gavins wrote:I think he already said in his prior post in another thread that the intake/airbox was stock, he also neglected to mention in this one it's restricted to 47bhp. It does sound like an intake issue though, missing the air scoop perhaps.