What would you do if you had the top sport ATV on the market? Yamaha chose to address all of the complaints-items such as the thumb-tiring throttle and lack of seat comfort-testers and consumers issued about its YFZ450. And, of course, update a few features to keep the competition reeling. Some 80 changes later, the 2006 model was ready to drop on the world.
We got our grubby mitts on the new blue machine at Castillo Ranch, north of Santa Barbara, California, and were duly impressed. Just sitting on the new YFZ brought to light the ergonomic improvements. The blue engineers left no stone unturned in their quest, and the new list begins at the aluminum front grab bar and ends at the LED taillight and rear aluminum grab bar. The engine received the intake tract and top end from the '05 YZ-F motocross bike along with a more robust, 1.4mm-longer stroke and grew from 439cc to a full 449cc. To match the bigger motor, the Keihin FCR carburetor and CDI received the necessary revisions, and an increased efficiency radiator was added to handle the higher heat output. A titanium heat shield rounds out the powerplant updates.
Stopping chores were enhanced with a twin-piston rear brake, relocated rear master cylinder and new brake pad material. The front brake lever also underwent a redesign in the search for improved feel. From new tires and a longer-travel (by 0.5 inch) rear shock to aluminum upper A-arms, the suspension was the focus of a major overhaul. The big deal is to effectively handle the improved output of the revamped 450 mill.
Did all of the changes work? Press the starter, thumb the throttle and we were greeted with notably easier action. The power pouring from the blue machine now starts off with good bottom and transforms into Yamaha's now-traditional five-valve screaming top-end. The track at Castillo Ranch proved to be the ideal proving grounds for the new machine with its hard-packed dirt, off-cambers and big hills countered by soft silt and loamy sections mixed with jumps of various sizes. The new Dunlops are surprisingly good general-purpose tires, and they provided exceptional traction, clawing over everything.
Whatever we thought about how good the '06 was, after the Yamaha techs replaced the stock silencer with a $339.95 GYT-R unit, installed the jet kit ($49.95) into the carb and removed the airbox lid, the YFZ450 was now a whole new animal. Just a new silencer unleashed the beast inside; now it barked off the bottom and ripped around the track. The funmeter was pegged as well. Its chassis updates kept up with the motor, and after a day of spinning laps, one of the testers felt he could race it with just the GYT-R can and hand protection installed. It's that good, and we are eager to see how the Yamaha compares to the rest of the class. They certainly have their work cut out for them to beat the blue motocrosser.
Adam Campbell-Photo GodIts very low center of gravity is great for MX type riding, and it never felt as if it was going to do anything weird. It tracked nicely over off-cambers as well as braking bumps and felt great on the test track. The suspension was on the stiff side, though its rigid feel does keep the rider in tune with the track.