ok heres what it says in dirtwheels they used a GPS to do speed runs
stock honda 450r ran a top speed of 78.9 mph
stock YFZ450 ran a top speed of 78.3 mph
the fastest yfz running runing 16/36 sprockets and 20s ran 87.3 mph
the fastest honda running 15/36 sprockets and 22s ran 88.8 mph