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.
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.
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.
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.
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.