This thread has been very surprisingly honest for speed claims. I remember when I first started people saying "kitted hobbit should be 60mph bike easy no problem".
7 years later my kitted hobbit is around 55mph (I've seen the GPS go higher but I don't believe it) and every mph after that is a struggle-- 70cc polini kit, MLM peoples pipe, TJT w/treats rumpus plate, VM18. I am most comfortable riding ~45mph for a top speed so what WillD is saying resonates. Unfortunately, where I live 50mph speed limits on streets is not uncommon.
The hobbit was my first and only bike. I've owned a stock 30mph puch freespirit and that was actually funner, at least around the neighborhood. On the streets is another story.