first off rime/tire size is gonna have alot to do with gearing what size you runnin? looks like 19/21. and what year yz is gonna play into it too unless you have a WR? my 05 yz450 only has a 4-speed currently no overdrive and im running 17" sumo rims/tires so my current gearing of 15/42 IIRC likes to cruiz at 55mph 5500rpmish is gonna be different for your 06+yz 07+wr itd probably cruiz better at like 65ish with 17"s you do that gearing now like 85ish maybe.
there is a gearing calculator stickied up top in the tech section try it out see what ya like at what rpm.... or are ya just looking for WFO speed thats slightly different?
COURSE we coud get a sticky goin for a standardized comparison!!! through "rollout" numbers hmmmmmm