Unlike the YZ450FX, which is intended for closed-course racing, the WR450F is an enduro bike equipped for more general use on public lands (though you certainly could all-out race it if you wanted). Advantages for the WR450F in this milieu include an automatic radiator fan system to control engine coolant temps in hot, sloggy conditions, special clutch tuning, added magneto circuitry that powers a halogen headlight and LED taillight, an LCD instrument display incorporating an enduro-ready computer, and durable Dunlop MX35 tires.
Interestingly, the WR450R shares the supercross-caliber YZ450F’s piston and camshaft specs, foretelling its savage pulling power; somehow, these work with a quieter muffler required for use in OHV areas. Otherwise, the WR450R mirrors the general pattern for Yamaha’s big off-road bikes: electric starting for the 449cc DOHC single; electronic fuel injection; a wide-ratio five-speed gearbox, an O-ring chain, and a speed-sensitive KYB fork backed up by a KYB shock, both of which provide more than a foot of finely tunable travel. Updates for 2018 include revised tire and suspension specs, and improved fork-seal wipers to better shrug off mud and slop.
Likes: Yamaha's priciest "cross-country" bike has the widest bandwidth of all
Dislikes: A chunky monkey at a claimed 271 pounds wet; not the world's best headlight
Verdict: Conquers anything, anywhere, anytime