Winning Demands Change
Winning Demands Change
A Look at the 1980 Daytona Superbike-Winning Yoshimura Suzuki
John Ulrich
In racing there is a word for people who don't improve their bikes every season. The word is loser. To win, development must never stop. Every year’s machine must be better than the last.
Lap times continue to fall, machines and entire classes travel around racetracks at quicker rates. To stand still in racebike development, to go with the status quo, is to be left behind.
So it is no surprise that the Yoshimura Suzuki GS1000 Graeme Crosby rode to victory at Daytona this year is significantly different from the Yoshimura Suzuki that Ron Pierce rode to victory at Daytona in 1979, just like Pierce’s bike (featured in our June, 1979 issue) was different from the Yoshimura Suzuki that Steve McLaughlin won Daytona with in 1978.
The major changes in this latest Suzuki Superbike are to the suspension. Up front, the special racing Kayaba forks have dif-> ferent valving to use thinner standard oil (20w vs the previously used 30w) because thinner oil reduces drag in the forks and allows faster response to irregularities in the track surface. Also new for 1980 is an entire range of fork springs to choose from in setting up the bike for a given track, adding fork spring rate to the other tunable variables of air pressure, spring spacer height (or preload), amount of oil and oil viscosity.
Winning Demands Chance
The rear shocks are also different. To start with, machinists at the Kayaba factory in Japan carved the shock bodies out of aluminum. Inside the damping has been changed, making it stiffer than in 1979. The shocks have 0.4 in. more travel, 3.5 in. vs the 3.1 in. travel last year. Length eye-to-eye is 13.5 in. for 1980, an increase of 0.6 in. The mounting position is changed, with less laydown angle.
The swing arm is extensively braced with bridging underneath. According to Pops Yoshimura, the bikes wobble if the bracing isn’t installed.
The engine, while still displacing 1023cc, puts out more power. Part of that power comes from the use of special crankshafts built by the Suzuki factory for the racing effort. But many of the racing cranks failed during the 1980 Daytona Speed Week, so it may be back to the drawing board. > The close-ratio transmission now has undercut engagement dogs for more posi tive and sure gear shifts. With increased undercut, it's almost impossible for the
Winnina Demands Chanae
bike to jump out of gear after an upshift. The shifting drum is different, too, using reverse radius cams. The practical effect is that the shifting drum followers
catch in the drum grooves and won’t kick out once they’re in, again reducing the likelihood of the bike jumping out of gear.
The exhaust system is probably the most noticeably different engine-related component on the 1980 racebike. The Yoshimuras used a small o.d. tailsection (favored this year by all the four-stroke race teams) and an external baffle, similar to the “boom boxes’’ seen on mile and half-mile dirt trackers. The smaller tail section o.d. improves ground clearance and leaves room for the external muffler while increasing power at the same time. The exhaust note is remarkably subdued for a racing four-stroke.
The 31 mm Keihin smoothbore carburetors are extensively modified and polished internally.
Wheels are a mix of Morris, Campagnolo and DyMag magnesium. Brakes are RG with larger-than-RG calipers and Grimeca front master cylinder.
Because the bike is officially based on the Suzuki GS 1000s this year, small handlebar-mounted fairings and windshields are fitted, a change which may not improve speed or handling but which definitely makes life easier for the rider at the 170mph top speeds the bike can reach.
For anybody interseted, Crosby’s bike is for sale for just $15,000. Contact Yoshimura R&D of America to order. B8
