Yoshimura history – 16

The 70mm cast piston, pictured here, featuring two piston rings (one compression, one oil), is the actual number 4 piston from the 1980 Suzuka 8H winner #12 Yoshimura Suzuki GS1000R.

Yoshimura History #16: The Decision that Secured the Second Suzuka Victory

1980: A Man with a Destiny

June 1980, Isle of Man TT. Pop and Graeme Crosby were upset. Pop, in perplexed disgust, submitted a complaint to the race organizer, and the earnest Kiwi racer was in utter confusion of what has just happened.

Graeme Crosby had won the Senior TT on a Suzuki GB RGB500 without a shadow of a doubt. The problem was about the TT-F1 (Tourist Trophy Formula One), which he entered on a Yoshimura Suzuki GS1000R (XR69) and finished second to race winner Mick Grant’s Honda RS1000 by just 10 seconds. TT-F1 is contested over 6 laps on the island’s 37.73-mile (60.72 km) public road course with 2 refueling stops. Mick Grant, however, only had to refuel once. There was a “trick” to it. According to the race regulations, the maximum fuel tank size allowed was 24 liters, but Grant’s RS1000 was equipped with a 28-liter tank, and his excuse was that he dropped some ping-pong balls into the tank in order to adjust its capacity. Grant was also seen banging the tank (as witnessed by Crosby) in a probable attempt to reduce its capacity. The other teams were also not convinced by this dubious explanation and made protests against race officials. But since Grant is one of the heroes of the Isle of Man, the result was final and was not going to be overturned. They were fed up.

Graeme Crosby’s #11 Yoshimura Suzuki GS1000R in a Texaco Heron color scheme. To Pop’s left, supporting the bike, is Suzuki GB mechanic Simon Tonge in his teens. Later, in his mid-20s, Tonge became Pepsi Suzuki Crew Chief for Kevin Schwantz. The Isle of Man TT is a major motorsport event in the UK, and one of the most important races for Suzuki Great Britain.

And came July of 1980, and the 3rd Suzuka 8 Hours Endurance Race had become a part of the FIM World Championship. The technical regulations for the Endurance Series were changed to conform to the then current TT-F1 (requiring the use of production-based four-stroke 601-1000cc or two-stroke 351-500cc engines), and Suzuka became officially the Endurance World Championship Round 6. Yoshimura —- Yoshimura R&D of America —- decided to pair the best riders available to Suzuki at that time, Graeme Crosby and Wes Cooley, on a factory GS1000R racer (XR69 with a φ70×64.8mm 997cc GS1000 engine). Crosby especially was an active GP500 rider who had shown incredible speed at both Daytona and the Isle of Man, and had become a force to be reckoned with among rival riders. Yoshimura also entered a second team consisting of Richard “Rich” Schlachter and Michael “Mike” Cole.

Team Manager for the 1980 Suzuka 8 Hours was Pop. Fujio did not make it to Japan this time, but his right-hand man, Yoshimura R&D mechanic Suehiro Watanabe, was sent to Suzuka together with Cooley.

1979 AMA Superbike Champion Wes Cooley aboard #12 GS1000R. In the 1980 Season, he had one win prior to the Suzuka 8 Hours, and was in a fierce championship battle with Eddie Lawson and Freddie Spencer who so far had won two races each. The three riders were to meet each other at Suzuka in their respective situations. It was another battle that they could not lose.

In qualifying, Crosby took pole position, followed just 0.07 seconds behind by David Aldana (paired with David Emde) on the steel-framed Moriwaki Monster Kawasaki Z1000. 3rd qualifier was Kawasaki’s leading rider Gregory “Gregg” Hansford who ranked 2nd in GP250 and 3rd in GP350 of both 1978 and 1979, and also raced in the AMA Daytona Superbike Series. His machine for Suzuka, KR1000, was developed in 1979 by the Kawasaki factory exclusively for TT-F1. The second-year model featured an asymmetrical chassis with a single, right-side mounted rear suspension and the Z1000J engine (998.6cc with φ69.4x66mm) which was designed with TT-F1 racing in mind. Hansford was paired with ex-flattracker Eddie Lawson, who had just joined the U.S. Kawasaki factory team in 1980 and had since won two AMA Superbike races.

1980 Yoshimura Suzuki GS1000R (XR69) after recent restoration. Everything is original except for the color of the rear springs and the absence of the Cycle World sticker on the swingarm. The Suzuka 8 Hours version of the machine was constructed around a chromoly double-cradle tube chassis with dual rear shocks —- the ultimate of its kind —- and featured a half fairing. The front engine mounts had been changed from rigid to rubber floating-type as a result of the lessons learned from the previous season’s experience.

July 27. The number of spectators at the Suzuka Circuit exceeded 100,000 for the first time, reaching 105,000. Shortly after the 8-hour race began, Freddie Spencer, a promising Honda rider on RS1000, had to retire after only 3 laps —- and therefore his teammate GP500 rider Virginio Ferrari could not leave the pit —- due to an “electrical issue” with loose connectors. Aldana (Moriwaki), who had been in contention for the lead in the early laps gradually lost ground, and as expected, it became a duel between #12 Cooley / Crosby (Yoshimura) and #11 Hansford / Lawson (Kawasaki).

By the 3rd hour, all but these two teams were lapped down. That meant the winner was either Yoshimura or Kawasaki. At Lap 110, during the 5th hour, a lapped down Cole (Yoshimura) was caught between the leader Crosby and 2nd-placed Lawson. As Lawson tried to overtake Cole at the hairpin, they collided and both went down, with Cole suffering a broken arm and retiring from the race. Lawson quickly got back on his bike and returned to the battle about 50 seconds behind Crosby. And when Lawson pitted shortly after, his team lost too much time to change the rear tire and was lapped by the race-leading #12. Victory seemed promised to Yoshimura.

The front forks are KYB 40mm right-side-up ANDF (hydraulic Anti Nose Dive Fork) with billet aluminum legs, but without quick-change axle. The rear axle, by contrast, is equipped with an ingenious quick-change mechanism, with both the brake disc (cast iron ventilated) and driven sprocket remaining on the swingarm (aluminum). The opposed 2-piston caliper on the rear is made of magnesium, and the bleed screws as well as some swingarm components are made of titanium.

Then, as Crosby aboard #12 made a scheduled pit stop for tires and fuel on Lap 130, he said, “The front brakes got spongy. Need to replace the pads!”

The brake pad replacement was unexpected, and the crew had not practiced it. Although they had prepared spare brake pads just in case, Kunio Asakawa, the mechanic in charge of the front section, broke into a cold sweat. He managed to compress brake caliper pistons with a flathead screwdriver and inserted new pads. The replacement took about one minute, and the entire pit stop took as much as about 3 minutes. Meanwhile, #11 Kawasaki flew past the pit wall twice, got back on the lead lap and eventually gained a lead of about 50 seconds over #12. Especially because the removed pads were “only” halfway worn, Asakawa was blamed by everyone on the team for the loss of the top position, and “was told, it’s because of you we lost the lead…or something like that. Pops (Pop) wouldn’t even talk to me,” he recalls.

Asakawa’s name was cleared after the race, when they took the machine apart at the Yoshimura factory in Atsugi, Kanagawa. It turned out that the front brakes were pretty much shot, and even the replaced brake pads were on the verge of failure. If Asakawa had not changed the pads at that moment, the bike would not have made it to the end and would have been in a much dangerous condition. Such “great fortune” would not have been possible without either Crosby’s accurate sensory perceptions or Asakawa’s prompt judgment.

Freehand machining at its finest. Yoshimura’s passion for victory is visible in the numerous lightening holes and dimples that had been drilled unevenly into the cylinder head of GS1000R.

The gap between race leader #11 Lawson and the chasing #12 Cooley was not closing, as they both had lap times in the 2:22s. At 5:48 PM, Cooley handed bike #12 over to his teammate Crosby, who then began lapping in the 2:20s, 2 seconds quicker than #11 Lawson. #12 Crosby took the lead as bike #11 was passed from Lawson to Hansford during its last pit stop and rider change at 6:24 PM. Bike #12 still had one more pit stop to make, and Pop was worried. Cooley had for years been suffering from diabetic fatigue, and Hansford was just too fast for him to contend with. Race rules prohibit one rider from riding more than 60% of the time, or more than 2 hours in a row. Crosby has been riding since 5:48 PM, so even with a cool-down lap after the 7:30 PM goal, it will still be less than 2 hours. Should the team let Crosby do a double-stint? Will he have the stamina for it?

The lightening holes in the upper shock mount brackets reveals the dauntless efforts for weight reduction, and yet Pop was critical of the GS1000R chassis for being “rather too heavy.” The rear suspension geometry has a diagonal (downward spreading) layout, and the shocks are connected with full pillow-ball mounts to ensure smooth operation. The endurance version of the GS1000R is retrofitted with an ACG (AC generator) that takes power from the drive sprocket. The ACG housing is casted with magnesium to save weight.

“You’ve got to go double-stint!” Pop shouted, as #12 Crosby pulled into pit with about a 40-second lead over #11 Hansford. Crosby was still in the lead when he pitted out with just a refuel. This short pit-stop without tire change was a good one. LIGHTS ON. Even after sunset, Crosby was still lapping in the 2:22s, as fast as daytime laps, while Hansford was in the 2:25s.

#12 Crosby of Yoshimura R&D took the checkered flag in 1st place, after completing 200 laps in 8 hours 1 minute 3.54 seconds. #11 Hansford of Team Kawasaki crossed the line in 2nd-place 40.26 seconds later on the same lap. 3rd place was snatched by #2 Marc Fontan / Herve Moineau riding the Honda France RS1000, and 4th place was taken by #14 Jean-Bernard Peyre / Pierre-Etienne Samin riding the Suzuki France (the predecessor of SERT: Suzuki Endurance Racing Team) GS1000R, with both teams finishing 3 laps behind the leaders. Yoshimura had now won two out of three Suzuka 8 Hours races, including the first event in 1978.

From left to right: 3rd place finisher Honda France’s Moineau; 1st place finisher Yoshimura R&D’s Cooley, Pop and Crosby; and 2nd place finisher Team Kawasaki’s Hansford and Lawson. In 1980, Suzuka 8H’s temporary podium was in front of the grandstand.

But there’s more to the story. Right after the race, just as Mechanic Asakawa was about to push the glorious #12 to the inspection area, he noticed how heavy the bike was and was shocked to found out that it had a flat tire. Taking a closer look, there was a nail or something in the rear tire. When in the world did this happen? If the bike had gotten a flat tire a lap earlier, it would have been a disaster. The team was again in luck. However, the business of being a mechanic is totally mechanical. After all, race mechanics don’t have the time to enjoy the podium champagne. Whether you win or lose, you’ve got to push your bike to the inspection area and look up at the post-race fireworks that indicate ONE JOB DONE…, so says Asakawa.

No matter whether they win or lose, Yoshimura race mechanics —- like other top teams —- disassemble their bikes after racing to check their mechanical condition. Some teams even do dyno-checks. So, after returning to Atsugi from Suzuka, they took #12’s engine apart. As they tried to remove the clutch housing, a roller bearing came out in pieces. A failure of the bearing would have resulted in damaging the oil pump, which will then cause the engine oil to run out.

There was a special collar that covers the outer race of the roller bearing. A small protrusion on the bearing outer race fits into a recess in the collar, so the collar has a specific direction in which it needs to be installed. And because, somehow, the collar was installed inside out, the bearing was crushed from excessive tightening. The race mechanics wondered how many laps the engine would have survived in that condition.

Thus, through a combination of hard riding, courageous decisions, and some good luck, the 1980 Suzuka 8 Hours was over.


Published on August 20, 2021

Stories and photos supplied by Yoshimura Japan / Cycle World / Tomoya Ishibashi

Written by Tomoya Ishibashi

Edited by Bike Bros Magazines

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