About 55-60 the most
Probably about 50-60
Yes, you just won't go as fast.
a mini bike with a 90 pound person on it that is 97cc can go 50mph
The answer depends on the person's mode of transport. In all likelihood, the person's mass is irrelevant.
Stock 13.80
Too fast!
The stock Bugatti Veyron goes 253 mph.
around 115 stock best quad made
With stock gearing around 63 mph
A stock Yamaha Banshee will go 77.7mph
70mph stock
No. not if it is stock.