Photography By Jake Ashcraft
Ever wonder how a showroom-stock 600-class sportbike would compare on the track with a kitted racebike? We did, so not long ago, Kawasaki Product Specialist Jeff Hoeppner and I took two 2008 ZX-6Rs—one stock, the other fitted with Kawasaki’s over-the-counter race kit—to Buttonwillow Raceway Park near Bakersfield, California, to answer that question.
We spent half a day dialing in the suspension on the $9099 stocker to make sure we got the most out of the standard equipment. I rode the bike as hard as safely possible until we were convinced that the 2:05 lap times that I was consistently clicking off were the best it could do in standard form, and then we moved on with the test.
After a burger and Red Bull break, I switched my focus to the second bike, a Kawasaki performance-parts-catalog poster child. Weight difference alone between the stock and race-kitted ZX6-R was 46 pounds, better than a 10 percent savings. Another difference is power output: On the CW dyno, the stocker made 100.8 horsepower and 43.3 ft.-lb. of torque; the kitted bike pumped out 112.5 hp and 43.8 ft.-lb. That may not seem like much of an improvement until you look at the dyno graph: At 12,200 rpm, the engine in the stock bike tailed off. The kitted machine, however, continued to pull until the rev-limiter kicked in at 14,900 rpm. At that point, the hot-rod engine had a 27.3-hp advantage. Talk about free-breathing.
Track-worthy mods weren’t limited only to improving power and reducing weight. Attack Performance clip-ons are slightly wider than the stock bars and designed to be replaced quickly. The KX450F rear master cylinder has a cleaner look and offered better feel. Adjustable Attack foot controls improved cornering clearance and weigh less than the stock pegs.
Switching from the stock Bridgestone BT-015 street tires to Dunlop’s latest race-compound D211 DOTs accounted for a massive increase in lateral grip and thus cornering speed. The addition of Öhlins fork internals and a fully adjustable TTX shock also made a big difference in corner-railing confidence. An Öhlins steering damper and Dynojet Quick Shift Kit further helped me better my lap times.
Out on track, the changes added up to consistent 1:58 lap times, a 7-second-per-lap improvement over what I’d done on the standard bike. If additional top-end power, substantial weight loss, superior suspension and improved traction are important to you, add $9,740 to the price of a ZX-6R and head over to your local Kawasaki dealer to order the race kit.
