There are several ways of calculating a bikes speed.

First is the vehicles top speed..literally what the vehicle will do at top whack,either stated by the manufacturer or independent testers.....often a few runs down a unused runway are what most bike magazines do.

Next measure of speed is Urban such as city use or A and B class roads...lots of uneven roads,bends and few straight/high speed stretches.

Test track speed checks are obviously done in a controlled and perfectly maintained environment where cornering speed,braking distance,acceleration and top speed can be measured.

On anything outside a motorway or racetrack,a Sportsbike can very quickly find its-self seriously hampered by the very merits that make them ideal on a track........Quick steering,hard suspension,powerfull brakes and aggresive acceleration can make a real world road into a nightmare....especially in the rain.

The Desmo would leave a sportster standing when on a racetrack or motorway,however as the road conditions worsen,the gap between the two bikes would get very much narrower.......but in truth,the sportsters suspension,brakes and groud clearence are actually not very good and will severley limit the harley after a while.

To see how a Motorcycle doesnt have to look fast to be fast....take a look at a well ridden BMWR 1200 GS,these are huge.bulky dual sport,heavy touring bikes ( Off-road/on-road capability ) One of the highest selling bikes in Britain....ridden by a good rider in town,or A and B roads.....these machines are un-catchable by sportsbikes.