When the Thunder Returns
WHEN THE THUNDER RETURNS
Four-stroke 1000s are scheduled to challenge the two-stroke 750s and 500s at Daytona.This is what they'll be like
John Ulrich
More things are unpredictable in racing than simply who will win a race. Take, for example, rules. Specifically, consider the rules for the 1980 Winston Pro Series road races.
As this is written, press releases have arrived from Daytona International Speedway stating that the 1980 Daytona 200 will be open to 1025cc four-strokes, 750cc two-strokes with 23mm intake restrictors, and unrestricted 500cc twostrokes.
Fine. But calls to the offices of the American Motorcyclist Assn. (AMA) (which Daytona officials say will sanction the 200), produce nothing but conversations with a secretary who says that nothing is official until the AMA Board of Trustees approves the formula for the races, and the next meeting of the trustees won’t happen until after this article finds its way well down the road to print.
Not to worry, Daytona officials assure us. There will be 1025cc four-strokes in the 200 and in other AMA races in 1980. And those four-strokes will be allowed GP frames and fairings and unlimited (within displacement rules) engine modifications.
Okay. So we'll stick our neck out and say that competitive 1025cc four-strokes will be allowed in the Daytona 200 at least, and probably the entire 1980 AMA season.
The appeal of letting the four-strokes in is that at least the engines will be based on the street bikes we all ride, which will make the bikes easier to identify with. In theory, the race fan should be able to cheer for his brand as well as his favorite rider, Flonda vs. Kawasaki vs. Suzuki vs. Yamaha. Because of its street roots, the new formula should boost interest in road racing. If nothing else, a big four-stroke sounds better than a 750 or 500cc two-stroke.
These aren’t Superbike Production racers. With special frames and full fairings, these bikes will be lighter, faster and better-handling than the Superbikes we know and love. They’ll probably be very close to the bikes we’ve featured here, and they’re going to be spectacular.
MORIWAKI KAWASAKI
You’ve probably never heard of Mamoru Moriwaki or his potent Kawasaki. But ridden by New Zealander Graeme Crosby, the bike set a new lap record for production-based motorcycles at Suzuka Circuit. Japan. Crosby’s record, set during the 1979 Suzuka Eight-Hours Endurance race, was 2:16.2. about half a second off the absolute Suzuka lap record held by Ikujiru Takai on a YZR750 Yamaha at 2:15.67. During the eight-hour race, until Crosby’s co-rider crashed it, Crosby and his Kawasaki were the fastest thing on wheels, pulling away from Yamaha factory rider Hideo Kanaya (YZR500) and a host of other factorybacked riders and machines from Honda, Kawasaki and Yamaha. Riding the same bike at the Isle of Man with stock carburetors (required by Formula One rules), Crosby reached 180 mph on one long straight. Fitted with CR Keihin carbs for Daytona, the Moriwaki Kawasaki should be right in the hunt with the best Yamahas for top speed.
A potential problem: The best bike isn’t any good without a fast rider. Crosby is considering a factory Suzuki offer for the world championship and Formula One.
and is likely to accept. Who will ride the Moriwaki bike?
The answer could be Ron Pierce, the man who won the Daytona Superbike race in 1979 and finished second in the 200 on the Yamaha Motor Canada Yamaha YZR750. Pierce was relieved from his position on the Yoshimura R&D of America Suzuki team for 1980 due to conflicts with head racing mechanic Suehiro Watanabe, and tentatively will ride for Moriwaki in 1980.
Who is this guy Moriwaki? He's the sonin-law of Pops Yoshimura, married to the former Namiko Yoshimura. He owns and operates an engineering and high-performance parts company in Suzuka City, Japan, and designed some of the Kawasaki parts sold worldw ide under the Yoshimura label until the summer of 1979. Then, a dispute with Pops and Fujio Yoshimura (who is in charge of Yoshimura R&D of America) over R&D emphasis and racing caused a family split with Moriwaki going his own way. Now. all Yoshimura Kawasaki and Honda parts are manufactured by the same company that made the Suzuki parts all along—a company headed by another son-in-law, Shohei Kato. Moriwaki, who disapproved of the heavy Yoshimura development emphasis on Suzuki and the recent resting-on-laurels vis-a-vis Kawasaki, is marketing and developing a full line of Kawasaki and Honda parts worldwide. His Daytona effort is part of his marketing strategy.
The bike itself has a chrome-moly chassis designed and built by Moriwaki. Wheelbase is 57.5 in., rake 27-27.5°, trail 100mm. The swing arm is 12mm shorter than stock and moves on needle roller bearings. The frame weighs 25.4 lb. compared to the stock frame’s 42.9 lb. Shock angle is 45°, and the Kayaba gas shocks are 12.6 in. long.
Forks are racing Kayabas. Brake discs are standard Kawasaki with Lockheed calipers in the front and a full-floating Lockheed rear brake assembly.
Moriwaki’s own pistons give an 11:1 compression ratio. Valves are 37.5mm intake and 31mm exhaust, compared to stock valve size of 36mm intake and 30mm exhaust. Cam timing is 26-56 on the intake and 56-26 on exhaust, compared to stock’s 30-70 and 70-30. Moriwaki ported and polished the head.
The crankshaft is a standard Zl-R part, with the tip of the crank cut off on the left side. Clutch is stock, except that clutch springs are shimmed 1mm for greater pressure. The transmission is a close ratio racing unit. Ignition is total-loss Krober CDI.
Wheels are Dymag cast magnesium, a WM2 in the front and a WM6 in the rear. Streamlining and controls are built by Moriwaki.
HONDA RS1000
Based on the CB900F. the RS1000 (as it is called by Honda UK) was built to eompete in English Formula One races. Formula One allows extensive engine modifications and a racing frame and fiberglass, but requires that standard crankcases and carburetors be used. With the exception of the carburetors, the bike that won the Suzuka Eight-Hours was a Formula Onespecification Honda ridden by Team Honda Australia’s Tony Hatton and Mick Cole. The Honda G B team of Ron Haslam and Alex George were second on another RS1000 in spite of losing a handful of gears (and re-gearing early in the race to carry on with three speeds), and Americans David Aldana and Dale Singleton had the race in hand before Singleton threw away a third RS1000.
Haslam and George finished one-two in the Formula One championship on the bikes, and Haslam in one race defeated Barry Sheene, who was riding a Yoshimura Dunstall Suzuki.
Bore and stroke of the Honda racer is 67.8 x 69mm for a displacement of 996cc. Honda is reluctant to release other engine specifications, but claims 125 bhp at 9500 rpm. Redline is 9700 rpm.
Ignition is total loss and the lubrication system is dry sump with the oil tank mounted behind the carburetors.
That is, the oil tank is mounted behind the carbs on the Formula One bikes. At Suzuka, Honda experimented in practice with fuel injection on several of the RS 1000s, finally abandoning the system for carburetors before the race. There’s no telling what Honda will run in the 200miler, since we couldn’t get any information on rules before presstime.
The racing frame has a head angle of 26° and 3.6 in. of trail. Forks and swing arm on the Suzuka bikes were equipped with quick-wheel-change fittings, essential for endurance races. There's no telling whether or not the Daytona bikes would incorporate the system.
The clutch is dry and the transmission has either five or six ratios, depending upon who’s telling. According to one set of RSI000 riders at Suzuka, the transmission of their bike had six speeds. Other teams said their bike had five speeds.
How likely is a Honda effort for Daytona? According to spokesmen at > American Honda, there’s a good possibility the bikes will appear, but nothing was certain at press time. Honda U.K. team manager Barry Symmons has expressed interest in racing at Daytona with his riders as well, presumably George (who won the 1979 Isle of Man F-l race with a faster average than Mike Hailwood turned on his RG500) and Haslam.
Likely American pilots, should American Honda enter, would include David Aldana. Steve McLaughlin. Ron Pierce and Freddie Spencer, providing Spencer can be pried off his Erv Kanemoto TZ750 for the 200-miler. Honda wanted Spencer to ride at Suzuka but was thwarted by Spencer’s sub-FIM-minimum age at the time. But Spencer has turned 18 since then, so that’s not a problem.
If the Hondas show up. they will be competitive.
YOSHIMURA SUZUKI
Pops Yoshimura has wanted to take on the TZs at Daytona for years, and has been experimenting seriously with GP-trim GS 1000s since late 1978. He also hates Honda, remembering old disputes and old races. He still revels in his 1978 Suzuka defeat of the mighty Honda RCBs w ith a Suzuki Superbike, and wants to deal Honda another blow as soon as possible. Pops' strong feelings toward Honda have moved him closer and closer to the Suzuki factory, culminating when he moved back to Japan to coordinate construction of a factory-framed, Yoshimura-engined endurance bike for 24-hour racing.
With the new rules for Daytona, a change of carburetors and removal of lighting systems could make an endurance bike competitive and Pops knows it. In a warm-up for the 24-hour events. Pops and crew appeared at Suzuka with two bikes built with factory support—new frames, new suspension, anti-dive forks, new brakes. The bikes didn’t work, and team riders Wes Cooley and Ron Pierce successfully argued for the removal of the antidive fork system and replacement of the swing arm and brakes before the race. In the event, the bike broke a connecting rod after myriad handling and braking problems. Back to the drawing board.
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By the Bol d’Or 24-hour. Suzuki engineers had come up with a new chassis, but a flat tire, a crash and a blown head gasket kept the bike, which qualified fourth with French riders, out of the results.
But the bike at least handled better.
Over the winter. Pops and the Suzuki engineers have been working non-stop on the project, even flying Cooley over for testing on the factory test track. Biggest remaining problems concern the crankshaft and connecting rods. It seems that the stamped sheet-metal main and rod bearing cages used on standard cranks deform and allow the rollers to move around after a period of time in a long endurance race. The pistons hit the head and the rods break soon after. Solid silver cages, welded cranks, and polished rods haven’t solved the problem, but if Suzuki wants to find an answer, the answer will be found.
W ith the changes being made constantly. we don’t know how close the Daytona bike will be to the Suzuka machine. All we have is Pops’ statement that the bike will weigh less than 350 lb. and will be a TZ eater.
According to Fujio Yoshimura. Yoshimura R&D will field at least one. and maybe two. machines. Cooley will ride for sure, with Aldana—who rode a Yoshimura GS in the AFM six-hour—a maybe. Looks like David Aldana’s Suzuka ride impressed more than Honda.
KAWASAKI KZR1000
There’s no telling if the Kawasaki factory' will really call their KZlOOO-based racer the KZR1000. but you can believe the thing is fast. At Suzuka a factory-built racer ridden by the brothers Tokuno qualified second only to Crosby’s Moriwaki Kawasaki. Another factory Kawasaki qualified 10th in the 60-bike field.
Like the others, the Kawasaki has a special frame and a production-based engine. The Kawasaki uses what look to be KR350 forks and KR750 brakes. Triple clamps are built-up rectangular aluminum. The sw'ing arm is built-up rectangular-cross section aluminum with eccentricaxle adjusters. Rectangular aluminum bridging is welded underneath the swing arm and a roller controls chain tension through the long travel. Shocks are laid down, and the fiberglass fuel tank looked better before it was repaired after a fiery practice-session crash.
Instead of cutting off the left end of the crankshaft and bolting on a shortened cover as Moriwaki did. the factory left the crank end on and exposed and fitted an oil seal.
SUZUKI GS1000R
Word is that the Suzuki factory will build and sell 1000 GS1000R racebikes for Formula One and Superbike Production racing. The bikes will probably have RGstyle frames and fiberglass, four-valvesper-cylinder. CR Keihin carburetors and all the other race trim. If that's so. the bikes could first appear at Daytona piloted by Heron Suzuki (UK) riders. Likely riders will include Graeme Crosby, newly pirated away from Kawasaki for Formula One and Grands Prix. It's also likely that any factory-backed Suzuki road racing effort in this country will be tied in with Yoshimura R&D of America, since the Yoshimuras were involved in development of the bikes.0
