The Ninja 250 thread eveolved into a discussion of the Yamaha RZ 350. This bike was a two stroke, which died due to emissions regs. Two strokes were incredible fast, but had huge HC emissions and sucked gasoline like pigs.
Evinrude (a division of Bombarier Recreational Products) makes direct injection two stroke outboards. Direct injection massively increases fuel economy in two stroke outboards with low HC and CO emissions.