Yamaha Yzf-R6
YAMAHA YZF-R6
Trial by Wire
BLAKE CONNER
MOTORCYCLE DESIGN has become very complicated. No longer can a company like Yamaha simply grab the most current technology from its race team, throw it on the latest repli-racer, improve power, reduce weight and wheelie off into the sunset. Think of the origicarbureted R6 as an LP, the previous generation a CD and the current iteration an MP3. Times have changed and so has the process of building bikes.
CW RIDING IMPRESSION
When I spoke with R6 project leader Kouichi Amano at the introduction of the 2008 model at Mazda Raceway Laguna Seca this past November, I learned that developing a modern sportbike like Yamaha’s latest middleweight requires a whole pile of compromises, including ratification by marketing types and bean counters, of course.
An electronics revolution in motorcycle design is well under way. No longer does the designer simply worry about cam profiles and compression ratios, but each generation of bike focuses more on gigabytes and high-tech solutions to solve problems that didn’t exist 10 years ago. According to Amano, the biggest hurdle is how to achieve more performance in this age of strict new emissions requirements.
In the past, the technology already existed; it was simply a matter of how much a company wanted to reduce the profit margin by using expensive materials and components. But squeezing the same amount of power-let alone more of it-out of new models has forced engineers to explore and implement technology like never before.
High-tech wizardry in the case of the R6 isn’t just marketing mumbo jumbo, Amano told me. Systems like the YCC-T fly-by-wire system (Yamaha Chip Controlled Throttle) and variable-intake-stack lengths ofYCC-I (Yamaha Chip Controlled Intake), twin injectors per cylinder with shower secondaries, and a closed-loop fuelinjection system with 02 sensor on the triple-catalyzed, EXUP-equipped exhaust system have become necessary components just to overcome the performance lost through meeting emissions standards.
Of course, a lot of the ideas come from the MotoGP R&D department. The race team isn’t worried about emis-
sions while ripping around Mugello or Laguna Seca, but new rules aimed at controlling fuel consumption (due to a maximum allowable tank capacity of 5.5 gallons) has forced it to become more efficient and savvy.
Amano said that his division and the racing team are constantly in communication. Both departments work on technologies that can benefit each; implementation is then dependent on the unique requirements of streetbikes or racebikes.
When it comes to middleweight weaponry, the R6 has long been a Cycle World favorite, topping the Ten Best awards in class in ’99, ’02 and ’05. A track favorite due to an almost unbalanced focus on that aspect of performance, the most recent generation perhaps pushed it a bit too far.
In the ’07 version of MasterBike (CW, August, 2007), the R6 failed to get rave subjective reviews, but that didn’t stop three riders from posting their fastest “supersports” time aboard it, our own Don Canet included. The same comments that swayed many away from it on track proved true during our street evaluation; keeping the YZF’s engine spinning into the stratosphere gets old while riding around town.
In addition to the mission of improving performance, Amano and his crew were also faced with the task of changing the engine’s character. The goal was to create a more user-friendly power delivery for the street without taking away racetrack potency. That meant expanding the powerband for more urge lower in the rev-range. Peak torque is now produced 1000 rpm earlier at 10,500.
New pistons raise compression from 12.8 to 13.1:1, and 83-percent larger crossover tubes between exhaust headers also contribute to additional midrange performance.
The winding Mazda Raceway Laguna Seca circuit just outside of Monterey, California, is ideal for the nimble R6; just ask Josh Herrin, who won the final AMA Supersport race of the season on his factory R6 there. Not only does the track put a premium on
only put a premium on
handling, it offers a lot of elevation changes that put a motor to the test.
Laguna’s layout helped me discover that the R6’s cornerexit drive is stronger than I remember the previous bike delivering. The YCC-I variable-length velocity stacks operate in their torque-enhancing 66mm-long position until 13,700 rpm, then the computer tells servos on the throttle bodies to raise the top half of the split stacks 25mm. That effectively leaves just the 26mm-long lower bellmouths, improving high-rpm intake velocity and top-end power.
On quite a few laps, I left the bike in third running downhill from the Corkscrew, just to see how it pulled the taller gear through Turns 9 and 10. The torque was more than sufficient and helped eliminate an extra upshift before downshifting to first for Tum 11.
Comer entry on the YZF is aided by an excellent slipper clutch in addition to ECU programming that doesn’t let the butterflies instantly slam shut when the throttle is closed, easing the transition to overmn. The computer also keeps the throttles slightly open to further reduce engine braking. The combined effect of these systems helped make the R6 ultra-stable on the brakes going into Laguna’s key final turn before the front straight.
Fuel-injection response was very good but not perfect. Exiting a few of the tighter corners like the Andretti Hairpin (Turn 2), the bike would momentarily stumble when I rolled open the throttle. The glitch was minor on the track, but we’re curious to see how the system performs on the road.
Razor-sharp handling remains the R6’s forté. A revised riding position pulls the rider farther forward and over the tank with lower handlebars.
In redesigning the chassis, Yamaha improved adjustability for track riders and racers, but the same components can be set up to improve a street rider’s comfort as well. The fully adjustable 41mm SOQI inverted fork has 10mmlonger top tubes, allowing compensation (via their position in the tripleclamps) for larger-diameter track tires or to permit the bike to be leveled for a more comfortable street posture. The same adjustments can be made to the fully adjustable SOQI shock, which uses shims above the top mount to achieve desired ride height.
Laguna has its share of fast sweepers in addition to the tricky noncambered Turns 3 and 4. Turn-in and grip were very good there despite cold morning track temperatures and street-oriented Dunlop Qualifier rubber. After getting some heat in the tires and tiptoeing through those underrepresented right-hand bends, the bike carved beautifully and was
very stable. Suspension damping and spring rates were excellent on the smooth new Laguna surface, only requiring some minor low-speed compression adjustments.
Despite gaining nine pounds (for a 366-pound claimed dry weight), the new $9599 R6 has made another leap in performance. Market demand and government restrictions will determine the DNA of the next-generation sportbike, but one thing Amano-san is sure of is that the current wave of technology is just the tip of the iceberg. Say goodbye to the LP and hello to MP3, because analog is no longer in the designer’s vocabulary. O
