are 50cc scooters highway illegal?

[DonBarletta]

I've been riding motorcycles and motorscooters for decades, and owned everything from 150cc to 1000cc. I would not want to ride any 50cc scooter anywhere, but if I had to it would be in town only and under 40 mph, because at 6'1" and 290 pounds the 50cc scooters are just too small physically and too slow (with no upper speed reserve) for my personal tastes.

My main current ride is a 2008 Kymco GrandVista, 250cc, that I bought last week with only 200 miles on it. It now has 410 miles on it and I just put gas in it for the second time, and it took about 1.6 gallons to fill up each time.

My gas log starts today, but just like my 250cc Honda Helix scooter, I imagine that this Kymco will get around 70-75 mpg. With the throttle wide open for a few seconds the other day on the interstate, the Kymco displayed 84 mph.

My other current ride is a BMW R100RT.