passing slower traffic in any low-powered vehicle is about proper planning. Just like at the race track.
If you're on a ninja 250 (or daily driving a 2003 corolla), you can't ride the ass of the car in front of you, then cut left and floor it to make a pass happen. You have to hang back, and start accelerating (hard) before the left lane is clear, and time it such that you're already closing on the car in front of you at a 10-15mph deficit when you move left and go around. Accelerate in your own lane, and make a pass at-speed. Don't get into a drag race with the guy you're passing when you're the one heading head-on into traffic.
At highway speeds, I agree, a 250 would start to struggle, but the principal is still the same. I don't encounter very many cars doing 90 on the highway, and unless a 250 is badly out of tune, it should hit 90. It probably takes a while to get to that speed, but it will do it.