The history of motocross has been a great revolutionary designs, followed by consolidation and the dramatic progress in improving motorcycle.
Moving from large impactors in the light two-stroke defined the 1960s. In the 70s, it was a long travel suspension. The '80s brought us the coolant and suspension links. The 90s saw the return of the four-time (not coincidentally, the Yamaha YZ400F) and the '00s saw a return to dominance Thumpers.
Yamaha, with the new YZ450F, fired first in the war for dominance '10s. This innovative feature motocross technical innovations that are highly desirable in the dust, and can have an impact on the bikes in the next decade to have.
The most obvious progress, of course, is the new engine with a cylinder, about eight degrees from vertical inclined backwards.
You can with the idea that centralization of the mass was the only reason for this radical transformation will be issued. However, the answer is more complicated than that.
Although the positioning of the weight of the YZ450F cylinder near the center of the wheel has certain advantages in handling, the cylinder is also offside 12-degrees forward of the axis of the centerline of the crankshaft something that has been made possible by leaning back of the cylinder.
In this position, the rod further into the rotation when the fire is a spark, but the stem at an angle where electricity is produced it, vertically, creating friction engine more efficient because of less-restrictive piston.