Here little 50cc scooters are pretty common:
this one is exatcly the same as I had years ago, with the same racing muffler:
http://www.indigosports.com/malaguti-phantom-f-12.jpg
They can be pretty fast.. I fully modified mine: sport suspensions, completely new racing engine, up to 80cc, new electronic management, new transmission and so on.. it wasn't all that fast: 100 km/h (62 mph), but here the limit for those scooter are fixed at 45 km/h by the law LOL (28 mph)... but the acceleration was a blast and at the stop lights, there wasn't competition for my little Phantom, really

even cars had problems with it in the 0-50 km/h...

and it was realiable: I did more than 10'000 with tha racing engine I think...