Since it’s complete and revolutionary redesign in 2010 the Yamaha YZ450F continues to get small tweaks and revisions each model year. For 2012 the list of changes are twice as long the previous year, but that still isn’t much. The engineers at Yamaha had their hands full with the2012 Yamaha YZ250F, so the focus on the YZ450F was to create a more linear powerband, better bump absorption and smoother shifting with minimal changes.
Last year in our 2011 450 Motocross Shootout the YZ450 was a hit with all of our test riders in terms of suspension performance and handling. Our crew lauded the virtues of the Kayaba 48mm Speed Sensitive System front fork and 50mm rear shock. This year the valving has been altered, but the spring rates have remained the same. The goal was to improve the bump absorption while reducing fore and aft pitching in the corners on braking and throttle application.
The first tire of the YZ450F stuck like glue in the corners, but the rear end didn’t provide the same amount of grip.
Right out of the gate the suspension difference was apparent. The new valving allowed us to power through the rougher sections of Glen Helen Raceway with more aggression and confidence. Headshake even on the choppier sections of the track at the end of the day was not on issue, and the reduced forward pitching on the brakes keeps things smooth going into chewed corners.
Handling wise we struggled a bit. The front end has phenominal grip in the corners and will take any line that you point it at. Feedback from the Dunlop Geomax MX51 lets you know right where you are in the traction department, and allows you to either stick in ruts or hold tight on flat corners. The problem is that the rear end likes to swing around much too easily. More than a few timea we had some hairy situations when the rear tire would lose grip and swing around while exiting flat corners hard on the gas. We think adding a bit more sag and dropping the rear would help out, but we ran out of testing time.
“I felt like a superhero when throwing the bike into a rut,” comments our tried and true tester rider, Frank Garcia. “On that note, I just wish the rear of the bike had as much grip as the front.”
Changes to the internals of the YZ450F engine is minimal with a more rigid shift fork to improve shifts from second to third gear. The fuel map and ignition time has been tweaked to provide a more linear power output and smoother throttle response at low to mid-RPMs. Lastly, the silencer has been lengthened 42mm, and the outlet has been reduced by 3mm to adhere to the AMA Pro Motocross sound level regulations of 94 dB.
Power output on the 2012 YZ450F is very similar to the 2011 model, but the initial snap has been mellowed out. The power is still impressive on the bottom end, but the light switch delivery is gone. Still you need to keep your wrist in check, as the rear end breaks loose easily and steps out with little provocation.
“The new ignition mapping for this year made some decent power improvements,” says Frankie. “But, I think the power of the bike was a little snappy and had me spinning up the rear wheel with just about every twist of the throttle.”
On the top end the YZ’s power tapers of quickly and lacks over-rev like some of the other 450 racers. It is definitely a bike that likes to be short shifted, but on longer tracks like Glen Helen more revs would be appreciated when grabbing another gear is just too much work right before having to brake for a corner.
Ergonomics on the YZ are just the same as 2011, which is a love/hate thing for our crew. Frankie was immediately comfortable behind the ProTaper bars and praised the flat seat and tank junction. He also felt the the seat to footpeg relationship was a bit cramped but helped with cornering.
“Another noticeable feature to the bike are the foot pegs, they seem to be a little on the high side but I did not find this to be a problem,” says Frankie. “It actually gave me some confidence when laying the bike over in the ruts and not having to worry about dragging them.”
I found the YZ450F cockpit cramped and awkward, feeling like I sat too high on the bike while the bars were too low. Standing was comfortable, but coming to grips with the compact layout took a couple of rides. Moving the bars forward in the clamps helped out significantly, but I still would prefer a taller set of bars to balance out the seat height to handlebar height.
With most of the 450-class machines receiving just a light going over, minus the 2012 Kawasaki KX450F, every bit helps in this ultra-competitive arena. Without a doubt Yamaha has made improvements to the 2012 YZ450F with a just few select changes. It will be very interesting to see how things will shake out when we line the YZ up its rivals for our 2012 450 Motocross Shootout.