http://faq.ninja250.org/wiki/Do_I_re...k-in_period%3F too.
Note that the CalSci, Motoman, and Duke methods all suggest getting it up to temp, then riding at a range of RPMs with engine loading and engine braking. While they may not be identical, they're all pretty similar.
On the other hand, Kawasaki has been putting that same break-in sticker on every bike for decades, regardless of the engine details. If you're into conspiracy theories, remember that they stand to make more money if your engine fails sooner (as long as it's not so soon that you feel ripped off).