My cousin has a yz250 and another cousin a yfz450 and the dirtbike will run away from him
in 100 yards putting about 10-12 bike lengths between them.
Tell your friend the only way the yz won't stand a chance is if he gets the 450 version.

 

Stock Raptors go 73-75 not 90 LOL, im not sure what the YZ does, if i had to guess i would say upper 70's

 

maybe 10 mph I've got an 01 that I got up to 83 mph according to my gps before I let off. I dont like leaving 2 strokes wide open for extended periods.