Dunlop Tire Test: Round 2 at Daytona

Photos by Brian J. Nelson

I attended the second Dunlop tire test at Daytona, January 17-18, where rider Eric Bostrom rode the Team Cycle World Attack Performance Kawasaki ZX-10R AMA Pro American SuperBike for the first time. The new ZX-10R is the bike that went on production hold for a possible high-rpm valve-spring surge. This issue has now been corrected by installation of an altered intake cam plus new intake springs and retainers. Crew chief Richard Stanboli told me he made the changes on the CW bike himself. “It took about an hour,” he said. Stanboli was pleased to find that valve clearances after the change did not require adjustment—evidence of good precision in cam manufacture.

The test was to have consisted of a half day Monday, 12–5 p.m., and a full day Tuesday. Atlantic Coast weather had other ideas: It rained all Monday, and residual dampness kept bikes off the track until after noon Tuesday.

It was just as well; no one is ever truly ready for Daytona. When I first saw the CW bike, it lacked wheels and fork legs, and was being wired for sensors. The press release announcing the team’s decision to race was dated January 14! Stanboli and his crew used every minute, and as soon as the bike was on wheels, it came down off the stand for rider Eric Bostrom’s “fitting,” a very important-but-sometimes-overlooked part of machine preparation. Where are the footpegs most comfortable? What brake-pedal height and shift-lever height? Hand controls and clip-on bar angles had to be set.

Anyone with Daytona experience knows that anything can happen on this big, fast track. Lots of big plans have turned to scrap in the first laps. But not this time. Bostrom went out on a really nice-looking bike with sponsor decals and numbers all carefully positioned—and he came straight back into the pit. He was running out of gear. The crew raised the gear, Bostrom went out again and was soon back, asking for an even smaller rear sprocket. Now, word came that he had tripped the AMA’s timer at 186 mph. Again, experienced persons discount official numbers; I heard 193 mph in 1974, and that was for a 125-hp Suzuki two-stroke Triple. Stanboli had the ZX engine briefly on the dyno, recording 190 hp in stock form (he never had the head off).

There are always problems. Bostrom indicated that through the chicane, the machine was making low-frequency plunging motions, pivoting off the rear. He wanted to go up on the rear spring rate, down on the front, to make the motion even, front-to-back. Later, he equipped himself with clipboard and paper, and carefully drew a circuit map with a felt pen. Then, he annotated the map with his impressions of the machine’s behavior at certain points. I asked if he has always used this method.

“Pretty much,” he replied. “It helps me get all my ideas out where I can see them together.”

Point by point, Bostrom’s concerns were either addressed on the spot or future solutions were planned (such as improved engine-braking control in the first-gear section of the short course that Daytona requires the big bikes to use). Smoother power onset was written into the upshifts. Spring rates were changed. By the time I left at 4 p.m. to catch my flight home, he officially had the fourth-fastest lap time. That was achieved with a stock engine and a MoTeC ECU that had its fuel and ignition maps reworked for best power. Rain or no rain, the outcome was encouraging.