Euromodder:
As far as pollution of two stroke bikes is concerned, you can always buy a low-smoke 2-stroke oil, these new oils are synthetic and on my 50cc scooter you cannot see any smoke from the exhaust and it also doesn`t smell as opposed to those old mineral 2-stroke oils. The other worst polluting is of course noise, but with a decent muffler it can be quieter than a car.
Christ:
Just remember to put on good brakes if you plan on going 50mph on a bicycle
