As you can imagine, a bike with a 70cc engine is not going to be a record-breaker but Honda claim the top speed to be 48mph, which should mean that it can at least keep up with most traffic on the overcrowded roads where I live.
Except that mine only seemed capable of around 40mph and that was a struggle. One day, I got so fed up with it that I wound the throttle right round and held it there (it was early on a Sunday morning so I had an empty road for a change) to see what would happen.