Motorcycle Racing News 2007 Yamaha YFZ-R1 | Feature

2007 Yamaha YFZ-R1 | Feature

In the vehemently contested liter-machine wars, manufacturers are allowing more technology to trickle down from their GP racing endeavors to their production line-ups in order to gain an edge over the increasingly fierce competition. In Yamaha’s case, some of the advances trickling down are coming from legendary 7-time World Champion Valentino Rossi. Intent on creating the omnipotent 1000cc sportbike, Yamaha brings to bear a host of MotoGP-inspired advances to the fifth generation YZF-R1. And it’s not all just marketing fodder for the brochure.

Since its introduction in 1998, the R1 has enjoyed an aggressively robust reputation in both aesthetics and performance. For 2007 Yamaha builds on this persona, refining it into an even more impressive package. Extensive wind tunnel testing renders the most slippery aerodynamics to date—right down to the screwless windscreen for minimum drag—allowing the R1 to effortlessly slice the atmosphere. The new bodywork is constructed of layered cowlings designed to draw heat away from the short-stroke 998cc DOHC, 16-valve, liquid-cooled, in-line four cylinder engine. The gas tank (4.75 gallon capacity) is a two-piece affair with fuel carried in the rear section for mass centralization of weight and the front half containing the airbox, which is fed by large Ram Air intakes to aid breathing.

The most significant rollover from Yamaha’s GP garage is the R1’s fly-by-wire throttle system. Officially trademarked YCCT (Yamaha Chip Controlled Throttle), it translates into the fact that twisting the throttle is no longer a mechanical operation. Instead, throttle input passes through a 32-bit ECU (Electronic Control Unit) fuel injection system that ultimately feeds the engine. This is the technology that’s been flying fighter jets for years and, despite the hocus-pocus concept of your throttle hand not actually operating the throttle valves, the system renders exceedingly precise, smooth and instantaneous power delivery. Click on image to enlarge.

Another highly sophisticated element unique to the R1 is the electronically controlled intake funnel length. At 10,500 rpm (with the throttle position electronically indicating aggressive acceleration) the intake funnels feeding fuel to the engine expand from 65mm to 140mm, increasing intake volume by 40 percent. The result is a substantial hit in the upper spectrum of the tachometer which is suited more so to track day outings than any legal—or sane—application on public roads.

Titanium 31mm intake valves, new high-lift cams, light and strong nutless connecting rods all contribute to a quick-revving engine. High silicon-content, ceramic-composite cylinder sleeves help dissipate heat and reduce friction for high rpm durability. Radiator capacity has been increased 13% and married to an aluminum liquid-cooled oil cooler for stable, consistent operating temperatures. The stock titanium underseat exhaust system emits a kind of turbine sound when downshifting, perfect accompaniment for the omni-present MotoGP fantasy.

The engine has a flat spot between 3,000 and 4,000 rpm, exaggerated by a bit of a hiccup off the bottom. In stop and go, slow moving traffic this is a nuisance. This minor glitch is forgiven by the R1’s tight engineering that syncopates clutch action, throttle response and gear changes into the realm of second nature, making it more than capable as a daily commuter—if you’re really intent on squandering this baby’s attributes sitting in bumper-to-bumper traffic. Although the engine may not be the most conducive for around town riding, the R1’s riding position is surprisingly comfortable—even for riders 5’10" and above. The cockpit is well stretched out with regard to the essential three points that comprise ergonomics: the handlebar/seat/footpeg relationship. Seat height is 33" and is complimented with a narrow mid-point for optimum leg reach to the pavement.

Despite the R1’s ability to handle urban outings, make no mistake about it, the bike was built to win races. In fact, all its race-inspired technology is somewhat wasted if the R1 owner never cuts the machine loose on the track. Dr. Robert Fleischner gave us the opportunity to do just that when he invited us out to attend an MTC track day (www.mtctrackdays.com) at Buttonwillow Raceway in California.  Click on image to enlarge.

As expected, (and eagerly anticipated, given the street test of the machine) the R1 took to the unrestricted environs of a closed course like a duck to water. The Yamaha was built to be ridden aggressively, delivering its best all around performance in a relatively narrow powerband between 9,000 and 12,000 rpm. While this kind of temperament is less than accommodating for a commute on public roads, it works seamlessly on a racetrack, where it’s much easier to keep the engine in its sweet spot. The result is an adrenaline rush of continually blurred peripheral vision.

A close-ratio, 6-speed transmission runs through a factory-installed slipper clutch, which can only truly be appreciated on a racetrack. The back torque-limiting clutch works by modulating engagement of the transmission with the engine, greatly reducing the possibility of hopping the rear wheel under aggressive downshifts. When ridden in anger, the slipper unit requires very little finesse, just pull it in, bang it down several gears, and drop the lever. The engine/transmission are automatically and gradually engaged without concern for getting the bike unsettled.

The new Delta Box aluminum frame has been tuned for optimum flex under intense structural demands at high speeds to help the machine absorb the stresses passing through it. The new truss style swingarm has been lengthened 16mm for added stability and is constructed to accommodate a wider race tire. Wheelbase is a tidy 55.7" and contributes to a fast, predictable turn-in, with wonderfully intuitive feel that makes hitting marks and apexes on a race circuit extremely easy—further exemplifying the influence from Yamaha’s Grand Prix garage.

To illustrate just how far engineers have gone to imbue the R1 with GP level performance, they chose to decrease the diameter size of the dual front brake rotors from 320mm to 310mm to reduce rotating mass. The 6-piston calipers are radial-mounted to deliver superior, stable stopping power. A Brembo radial-pump front master cylinder—with an adjustable lever—is employed for improved power and feel. Rear unit is a single 220mm disc grabbed by a single-piston caliper. Click on image to enlarge.

Inverted 43mm KYB forks with adjustable preload, compression damping, and rebound damping handle suspension on the front. The rear is suspended by a single shock with adjustable hi/lo-speed compression damping, rebound, and spring preload. Hollow bolts and various lightweight fasteners, along with lightweight five-spoke wheels contribute to the R1’s claimed dry weight of 390 pounds.

The R1 is a serious race machine, the result of building off technology from the GP wars. It deserves the wide-open expanses of a race circuit. To take possession of one of these thoroughbreds and keep it within the legal and responsible—not to mention sane—confines of public roads is a travesty, bordering on the unjust. Don’t let all of Valentino’s hard work go unrewarded. Although the R1 is a beautiful canyon bike and can handle the daily grind, do yourself and the bike a favor and take it to the track occasionally.
 
www.yamaha-motor.com 

 

RIDING STYLE
Helmet: AGV XR-2
Leathers and gloves: Dainese
Boots: Sidi Vertigo Corsa

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