My reply, "60 mph," impressed him momentarily. I'm gonna guess he's a motorcycle rider, because he then asked how stable it was at that speed. I gave a hand motion to say "so, so" and commented that my bike has 10 inch wheels.
Since we were idling at a light and I was communicating through a full face helmet, I pretty much kept it at that. In case you're interested in a little more detail about how fast these things we call scooters go, read on.
My daily rider, a Stella by Genuine Scooter Company, can indeed reach an indicated (by my speedometer) speed of 60 mph or a tad higher. This bike has a 150 cc engine and a Sito Plus exhaust, which gives me a little more umph up hills. Very generally speaking, the size of the engine in cubic centimeters (cc) has the most to do with how fast a scooter goes.
For comparison, my fist scooter, a Yamaha Vino, has a 50 cc engine (no performance upgrades) and can go 40 mph or so if you're headed downhill and have a head start--which means you can expect to top out on a flat road closer to 35 mph. Expect to decelerate on steep hills.
Engine sizes for modern scooters commonly range from 50 to 250 cc--so expect top speeds of 30 to 70 mph respectively on a stock (unmodified) bike. I won't get into the host of performance options that give you more power in this post.
Maxi-scooters, the big boys, range in engine size from 250 to 650 cc--just in case you wanted to go 100 mph on a scooter!