2008 600cc Sportbike Comparison - Balancing Act

The Triumph has a big advantage in horsepower and torque that pays off on the street, but with little overrev and a harsh rev limiter that power is difficult to maximize on the track. The screaming Yamaha still lags in the midrange department, while the Kawasaki runs out of breath up top. The Suzuki's torque advantage from 5000 to 8000 rpm is easily noticeable on the street, but top-end power feels less than the dyno indicates.

The Yamaha's lower clip-ons for this year put noticeably more weight on the rider's wrists and show the R6's racetrack intentions. The Kawasaki with its low, roomy seat rated highest for racetrack ergos; the Honda-with higher clip-ons-scored highest for street use.

The thrust chart, which relates driving force to speed on the road, puts the dyno chart into perspective. The Suzuki's tall gearing (note the higher top speeds in each gear) puts effectively less power to the ground at any given speed, while the Kawasaki's close-ratio box makes up for a lot of its power deficiencies in the higher gears. The Yamaha has the most thrust at maximum speed in each gear, but the valleys in the curves show how important it is to keep the engine spinning near redline.

The Daytona 675 is the sixth-gear roll-on king, matching short gearing and stomping torque to make quick work of this test. The Yamaha is way below the meat of its powerband while the other four-cylinders crisscross in between those two extremes.

At HPCC the Honda and Triumph blasted through the quarter-mile equally quickly, combining smooth clutches and torquey engines with good top-end power. The Yamaha and Kawasaki are both difficult to launch; while the R6 can use its strong top end to make up for a poor start, the Kawasaki cannot. Launch rpm for the Yamaha run shown here was 14,000 rpm. Ouch.

If you've perused any of the Kawasaki forums, you've undoubtedly heard of the popular "jumper mod" that can be performed on the ZX-6R to unlock the European mapping inside the ECU. We made the modification-a simple matter of inserting a wire in a connector under the seat-while at the dyno, and the results are shown here: a stunning increase in peak power that puts the ZX-6R on about equal footing with the Suzuki and makes a huge difference in top-end performance. We slipped the wire in partway through our top-speed testing as well, and the Kawasaki leaped from the back of the pack (154.4 mph) to almost the front with an increase of more than 5 mph to 160.1 mph. We're not certain of the reliability, warranty or emissions ramifications of the upgrade, but if you ride your ZX-6R on the track regularly it's worth some investigation.