Originally Posted by yorkie_chris

Yes you do.

A can isnt going to add enough performance to put it over 33bhp, even if it did theres no way they could do you for it, if your bike was shown to be making 33.5bhp then you could just argue the toss about the accuracy of their dyno. And it would certainly be restricted, as it wouldn't be making 70bhp
Though your certificate will say for a standard bike, if it came to it just claim ignorance and remember its up to the coppers to prove that your bike is over 33bhp, not up to you to prove its less than.

Chris