Am I too big for this motorcycle?

N250RC Grand Poobah Leon is about 6'2", and he's got over 100,000 miles on one of his 250's. Many people on 250's (Jeb/Andrew/Daryl) are around 5'10"-6'. Weight is actually the more important factor; anyone over 250 lbs. or so might want to consider the ex500 or 650R.

This guy, while seeming to have some trouble staying on the seat, isn't complaining much, and he's at least 6'4" and on the far side of 250 lbs.

The ex250 is small, but so are most sport bikes. That's the whole idea - that they're fast and lightweight, and small. If posing is what's important, buy an R6. If having fun is important, buy a 250 - They're a blast!

One of the members made a good suggestion. Since the dealer won't let you do any sort of test ride to see how you'll fit for a long ride, sit on the bike at the dealer for about 30-45 minutes, and see how you feel. Or go find a used 250 and take it on a test ride.