The sport ATV market is alive and well--witness Yamaha quoting a 226 percent increase in sport ATV sales over the last six years. With this in mind, Big Blue gave both of its sport quads, the YFZ450 and Raptor, a lot more than just a BNG treatment.
YFZ450
The racing-focused 450 received a host of changes mostly aimed at more power and better delivery--the short version is the YZ450F motocrosser top end was bolted onto the ATV powerplant to get healthier low to mid power. The spaces between the valve seats on this new top end were smoothed out on the squish dome, which lowered compression just a hair, while the intake tract was narrowed, boosting the low to midrange but supplying the additional ponies in a more manageable manner. The rod grew longer (by 1.4mm) and was thickened to increase strength, so now the displacement is a full 449cc. More power means more heat, so to handle the challenge cooling capacity was increased 19 percent via a higher density of fins in the radiator. New ignition mapping accompanies the hardware changes to complete the engine overhaul, of course.
A bigger rear brake, an eccentric chain adjuster and an improved skid plate.
Attention to rider comfort was the second point for the design team. They began by adding 15mm of seat foam on the sides as well as the top. Next came a rethought handlebar and mount setup. The overall bar height is up 5mm via a 20mm-taller mount and a 15mm-flatter bar bend--Yamaha acknowledged owners are going to replace its bars anyway, so why not make it easier to add a flatter bar by making a taller mount. Controls were also tweaked, with the throttle-lever action decreasing by 20 percent for reduced fatigue and the rear brake switching from a single-piston to a two-piston system. This required a higher-capacity reservoir, which was also relocated.
Both Yamahas share the blue A-arms.
The engineers didn't stop there; they installed a 13mm-longer shock with a dual-rate spring and an eccentric chain-adjuster system on the swingarm that allows the rider to adjust chain tension on the trail with the supplied tool kit. The YFZ450 is offered in the standard Yamaha blue/white scheme or a white/silver outfit, both sporting blue A-arms. A third option is the limited-edition Bill Ballance Edition, which has his graphics and the GYT-R accessories installed by the dealer.
A thumb-friendly throttle was one of the YFZ450's updates.
Raptor 700R
As exciting as refinements are to the 450, the big news is the all-new Raptor. The sharp-eyed might have noticed the 700R already, but we do mean all-new here. About the only parts in common with last year's 660R beyond the Raptor name are the chevron styling on the front and the signature blue color. As with the YFZ, comfort was a major goal on the Raptor, but so were improved handling and more power. In the process everything was changed on the machine.
The part-steel, part-aluminum frame equals better handling with less weight.
Engine displacement grew to 686cc while the overall size became more compact. The head is 21 percent lighter than the 660's through a simplified four-valve SOHC system that also offers up less friction thanks to needle bearings in the right places and a lower number of moving parts inside. The piston is forged aluminum, and a twin counterbalancer setup stifles the vibrations. A Yamaha Fuel Injection (YFI) system controlled by a 16-bit ECU that handles the jetting chores from 600 feet below to 15,000 feet above sea level was added along with a fuel pump that's built into the gas tank. (There's the first challenge for the aftermarket: Build a larger-capacity tank with a pump.) The YFI does away with a choke, and should the owner decide to remove the airbox lid or install a slip-on muffler, its ECU can compensate for the changes since there is no O2 sensor on the exhaust. Handling this output is a five-speed transmission with revised reverse gearing and a new no-link shifter.
Both units have a host of GYT-R components available, such as this oval silencer.
As if a major engine transformation wasn't enough, Yamaha engineers also changed the chassis and body styling. Under the reshaped and better-padded seat and new plastic is a steel and aluminum hybrid frame that enabled engineers to redistribute the weight bias to 5 pounds more up front and 17 less in the rear, lengthen the wheelbase 1.5 inches and widen the rear wheelbase width 2.5 inches. Thanks to the 7-pound-lighter frame, the 700R is 2 pounds lighter than the 660R at 396 pounds despite its displacement increase. The new machine shares A-arms, similar controls and a nearly identical steering geometry with the YFZ450.
In this cutaway of the 686cc engine, the white gizmo at the top is the fuel pump.
Both ATVs received new Dunlop tires mounted on aluminum rims to round out the handling improvements. The Raptor also saw an improved rear suspension setup, gaining a whopping 1.4 inches of travel. It also got the new eccentric chain-adjuster system and a white/silver color option to the standard blue/white scheme. Both Yamahas wear more durable LED taillights, and easy-to-grab bars at both ends help move these babies around. We can't wait to get our first taste of the Raptor in the next ATVR.
2006 Yamaha YFZ450
Retail price: $6999; Bill Ballance Edition, $7449
Engine
Type: Single-cylinder, four-stroke, titanium five-valve DOHC
Displacement: 449cc
Bore x stroke: 95x63.4mm
Cooling: Liquid-cooled with fan assist
Carburetion: Keihin 39mm FCR with Throttle Position Sensor
Starting: Electric
There's no missing the late-'50s-era fins on the big Yammie that make it look part Batmobile.
Drivetrain
Drive system: Sealed O-ring chain, eccentric adjustment, 2x4
Transmission: 5-speed manual
Suspension (Type/Travel)
Front: Independent dual A-arms/9.1 in.
Rear: Cast-aluminum swingarm/10.6 in.
Brakes
Front: Dual hydraulic discs, twin-piston
Rear: Hydraulic disc, twin-piston
Tires
Front: 21x7-10 Dunlop AT radial
Rear: 20x10-9 Dunlop AT radial
Dimensions
Wheelbase: 50.4 in.
Claimed dry weight: 350 lb
Ground clearance: 4.4 in.
Length/width/height: 72.4/46.1/42.9 in.
Seat height: 31.9 in.
Fuel capacity: 2.6 gal.
2006 Yamaha Raptor 700R
Retail price: $6999
Engine
Type: Single-cylinder, four-stroke SOHC
Displacement: 686cc
Bore x stroke: 102x84mm
Cooling: Liquid-cooled with fan assist
Carburetion: Yamaha Fuel Injection (YFI), 44mm
Starting: Electric
Drivetrain
Drive system: Sealed O-ring chain, eccentric adjustment, 2x4
Transmission: 5-speed manual with reverse
Suspension (Type/Travel)
Front: Independent dual A-arms/9.1 in.
Rear: Cast-aluminum swingarm/10.1 in.
Brakes
Front: Dual hydraulic discs, twin-piston
Rear: Hydraulic disc
Tires
Front: 21x7-10 Dunlop AT radial
Rear: 20x10-9 Dunlop AT radial
Dimensions
Wheelbase: 50.4 in.
Claimed dry weight: 396 lb
Ground clearance: 4.4 in.
Length/width/height: 72.6/46.1/44.5 in.
Seat height: 32.0 in.
Fuel capacity: 2.9 gal.