In some states of Australia, the 50cc scoot is restricted to a top speed of 50km/h which just so happens to be equivalent to 1 km/h per cc. Derestricted, a el cheapo 50cc scoot is capable of 65 km/h quite easily. Then you have the sports models such as the Ludix for example which is capable of 80kmh, more than 1.5 km/h per cc capacity. Then, the almighty Aprillia SR50 that is rumoured to be able to crack the ton, 100 km/h. That’s two km/h per cc capacity.
If you have a motorbike capable of such speeds, that is, 2 kilometres per hour for every cc of capacity then please contact the guiness book of world records and proceed to your nearest salt lake flat.