There was a model made from 2003-2007, that has 8 engine slots and no fork stops in the front, it is usually a orangeish color.The forks were angled. The model made from 2007- 2010 has 4 slots and fork stops, and came in yellow, red, and green. The forks were angled. The new model has a completely different look, such as the frame rails flare out and angle up at the end of the bike, and the forks are completely straight.