<P> Despite these perceived shortcomings, the 2006 Kawasaki KX450F would win both the AMA World Supercross GP title and the BooKoo Arenacross title, as well as the Hare and Hound title . </P> <P> For 2007 the KX450F received a series of minor engine and frame refinements, but its most notable upgrade was a 5 - speed transmission . The transmission received a slightly taller 1st gear, while second through forth remained the same and the fifth added . </P> <P> The next major innovation would be in 2009, as Kawasaki introduced fuel injected . Reviewers raved of the performance effect of the new injectors, and in proceeding years the technology would spread across the KX lineup . </P> <P> A series of major revisions came in 2012 . The KX450F received an all new frame, significant engine modifications and a new electronics set that included Launch Control . Launch Control is designed to prevent wheel - spin at take off, and automatically disengages once third gear is reached . It is activated by holding a switch until an indicator light glows green, at which point the bikes computer modifies acceleration factors . Kawasaki has continued to insist since inception (for safety reasons) that this system is not traction control but a unique system onto itself . </P>

When did they start making fuel injected dirt bikes