The heart of the WR450F is a 5-valve, liquid cooled, 449cc powerplant with a 39mm Kehin flat-slide carb.
"The WR offers great power for trail riding," reports veteran rider Brian Chamberlain. "It didn't hit nearly as hard as the YZ, but the trade-off was that the WR power is always useable. The YZ hits almost hit too hard at times, spinning the rear tire with ease, especially when riding on a hard slick surface. It can spin immediately before hooking up and pulling real hard in whatever direction it is pointed."
Both bikes can be ridden slowly through steep or technical terrain like a good 4-stroke should, but there's little room for error with the throttle on the wild-stallion YZ. Although it does possess good bottom-end power, its gearing is just tall enough to cause inopportune stalling when the going gets slow, and it is difficult to keep the bike moving when the trail is technical.
Obviously a gearing change would address that issue, but it would then lose top-end speed. This is where the 4-speed transmission presents a problem unlike the 5-speed box of the WR. Add an additional gear and the bike would instantly gains points for real-world versatility. Without it, the WR has a decided advantage over the YZ (or a Honda CRF for that matter).
Since the WR is capable of slow or high speeds, it opens the door for a decision to be made. Ride WFO and take no prisoners or take it easy and pick the safest route past the rough stuff. Either way is fine with the WR because it does both very well.
Mud bogs really don't pose a serious threat to the WR but it was fun trying to get across without getting a face full of the gooey earth shoved in your unsuspecting pie-hole!
"The WR never had too much power," explains test rider Scot 'Crash' Gibson. "It is more appropriate to say it has just enough."
While other test riders agreed with Gibson, his sentiments were not shared by everyone.
"The WR is a fun woods bike that feels similar to the YZ450
, minus all that great power," said Joe 'Rizzo' Wallace. "The YZ in contrast just wants to haul ass, and it is at its best past half throttle when traction is no longer as big of a concern as the rapidly approaching conifers."
At one point during testing, a trio of us rode to the end of a trailhead and back onto one of the many curvy fire roads around this area. This particular mission included a CRF for reference purposes. As the YZ and CRF riders bombed up the bank and onto the road, hanging huge wheelies as they headed into the horizon, I opened up the WR and had a moment of clarity.