Take a look at his Aprilia advertised locally, http://www.gumtree.com/p/cars-vans-motorbikes/50cc-moped-aprilia-sr50r/1011681668 90mph???
Never, not even nearly, the forces needed to get to 90 are well out of the realm of a 49cc engine, there's an interesting read in practice sports bike (I think) they are try to get a 50 to do a 100mph, but the changes needed are in the realms of rocket scientist and formular 1 engineers, and they are struggling to get it past 70. So while the ad might be true, I smell bull$hit. 18 bhp? Ha ha haa...
