New YFZ450 Woods Racer

[MOTOCROSS MAVERICK]

Track To Trail: Yamaha Unveils YFZ450 With Woods Appeal

By John Prusak on November 16, 2009 at 11:44 am

A year ago, Yamaha took the wraps off a brand new 450 sport quad that was so exciting that our former sister publication, ATV Sport, named the YFZ450R its “Sport Quad of the Year.”
The machine featured a lighter chassis, higher-performance engine, upgraded suspension, improved ergonomics and several other upgrades over the standard YFZ450. Motocross racers and dune riders gushed about the machine and raved about its prowess, to the point where trail riders and others who purchased a standard YFZ couldn’t help but to feel a little bit jealous.
“Where’s our faster acceleration?” they asked. And suddenly the ergonomics and suspension that felt so right on the standard YFZ450 now felt dated after knowing what else was possible.
Yamaha folks dodged the direct questions, and talked about the new R version as being a special edition of sorts. But they also seemed to avoid eye contact when confronted about the possibilities about a slightly more narrow, trail-oriented version of this upgraded YFZ. Clearly, they were hiding something – until now.
Big blue has taken the wraps off its 2010 lineup, and the star attraction is a new model called the YFZ450X. By doing so, Yamaha did more than just claim its own stake to the 24th letter in the alphabet (think about it – DVX, DS 450 X, TRX 700XX, KFX, 525 XC, MXR, 450 MX, etc), it infused fresh life into a sport quad market that is threatening to grow stagnant, given the state of that end of the scene right now.
For 2010, Yamaha also added some new colors to a few of its models, including the top Grizzly and the popular Raptor 250, while dropping two models that hadn’t been pulling their weight the last couple of years (the Big Bear 250 and Wolverine 350).
But for 2010, the big news is the newest X.
450X Marks The Spot
OK, quick show of hands, who would like the following features on a sport ATV: A faster revving engine; more suspension travel; better, more adjustable shocks; a roomier cockpit with a better seat and better handlebars; a lighter frame; stronger but lighter wheels; better handling in tight conditions; and a better, more precise fuel delivery system? Those without their hands up can leave the room.
Seeing that you’re all still here, it’s time to share some details.
The YFZ450X is really a YFZ450R that’s made for woods racers and aggressive trail riders who want a narrower stance for picking their way between the trees. The easiest way to tell the difference between the R and the X is the width, but there are notable differences between the models. The wider R is aimed at the motocross racers and desert free riders, while the narrower X is for aggressive trail riders and cross country racers.
The base frame on both models is a combination on no-weld cast aluminum and high-tension steel, and it’s 15 percent lighter than the traditional YFZ chassis. Cradled in its center is a high-output, fuel-injected version of the 449cc four-stroke single.
The engine is quite different than the standard YFZ, but the same as was introduced on last year’s R models. It features the titanium, five-valve cylinder head and cylinder found on Yamaha’s YZ450F dirt bike. The engine cases and transmission gears were beefed up for durability, and intake and exhaust ports are revised for more linear acceleration. Fuel is delivered through a 42mm throttle body instead of a 39mm carb.
One hidden difference between the R and the X, according to Yamaha’s Pat Biolsi, is the fuel injection mapping.
“When you are in the tight, technical woods areas, when you blip the throttle you blip it in a different way than you do on a track or when in the desert,” he explained. “You actually blip it just as quickly but you blip it a little bit less, so we really focused on the mapping. When you get into bad traction areas or when you get a lot of mud on tree roots or rocks or things like that, we really wanted to focus on rear traction and the fuel injection mapping, making the throttle response that much cleaner, quicker and smoother in those situations.”
The biggest difference between the models is in the front suspension. The X version has shorter A-arms that help create a 46.1-inch stance vs. the 48.8-inch stance on the R.
“But we didn’t just narrow up the A-arms and axles,” Biolsi pointed out. “The A-arms are totally redesigned.” Both use the same highly-adjustable, piggyback shocks, with adjustments for high- and low-speed compression, plus rebound and preload. But the way the shocks mount to the A-arms is different.
“By changing the lower mounting position on the lower A-arm, that drastically changes the leverage ratio that works on the shocks, and that gave us the plush feeling we wanted when going over tree roots, rocks, things of that nature,” Biolsi said. “That’s really important when you’re trying to reduce fatigue and make a more enjoyable experience for the rider. Whether you’re a recreational rider or you’re racing, like a GNCC-type rider, you really want to be able to go over those really gnarly, tight, technical sections with minimal negative feedback to the rider.”
Also, to make the quad handle better in tight quarters, Yamaha reduced the caster angle (from 5 degrees to 4) and trail (from 21mm to 18) on the front end. One degree and 3mm may sound puny, but the changes reduce steering effort and aid in tighter handling between the trees, Biolsi explained. We can’t wait to find out for ourselves.
Other than being 2 inches more narrow, the rear suspension is essentially the same between the two X and R models, but notably better than the standard YFZ450, though the shock and spring settings should offer a slightly more plush ride on the X, Yamaha said.
Ergonomically, riders get all of the advantages found on last year’s popular R model, including a mega-comfortable seat that’s narrower at the front and fat, wide and plush at the rear. The fuel tank has cushioned, textured side panels, perfect for hugging with your knees. The aluminum Pro Taper handlebars are adjustable to four positions. The throttle comes in a new shape, plus it’s got a much easier pull, thanks to the move to fuel injection (vs. carbs on the standard YFZ last year).
A special Bill Ballance Edition of the 450X will be available with racing graphics and frame, a gold chain, silver wheels, quick-release fasteners on the body work and a special grab bar and number plate up front.
Both the R and X models come with new wheels that are lighter and stronger, thanks to a new inner-rolled lip.
We spent a lot of time on the YFZ450R last year, and loved it. We haven’t ridden the YFZ450X yet, but are eager to get the chance.

[xzpolskix]

Good to see Yamaha rejuvenating its lineup. Sounds like this thing is gonna be a beast in the woods allowing you off-roaders to go into narrower places.