The Suzuka 8 Hours has been the world’s most important motorcycle race for the past 30 years. The Japanese bike industry pours more money and resources into winning the event than any other single race – but it wasn’t always this way.

The first 8 Hours grew out of the popular six-hour scene in Japan, the USA and Australia, where the Castrol Six Hours for bog-stock bikes was one of the world’s best-known races.

Honda spent most of the 1970s out of Grand Prix racing, sulking at the two-stroke takeover and spending its money on the FIM Coupe d’Endurance series, including the hugely popular Le Mans and Bol d’Or 24-hour race. It was inevitable Honda would want to show off its successful RCB1000 endurance bikes (based around bored-out CB750 engines) at its home circuit: hence the Suzuka 8 Hours.

The race was hugely important to the company from the outset, with Soichiro Honda turning up at Suzuka (half a mile from his biggest factory) to tell his engineers that victory must be theirs. But as much as Honda wanted to win, Hideo ‘Pops’ Yoshimura wanted to stop them.

The two companies had fallen out with each other a decade earlier, when Yoshimura was tuning Honda car engines.

“When we tuned cars in the late 1960s, we didn’t do chassis parts, so they came from Honda,” recalls Fujio Yoshimura, son of Pops (who died in 1995). “Sooner or later Honda stopped us getting the chassis kits. That’s when the war started, so there was a big desire to beat Honda!”

But how could a small tuning business founded on an island off the Japanese mainland defeat the world’s biggest motorcycle manufacturer?

Honda’s Suzuka line-up was impressive: its number-one team comprised endurance legends Jean-Claude Chemarin and Christian Léon, who had already won three endurance rounds that year, including the punishing 24-hour street race run through Barcelona’s Montjuic Park. Back then, two riders did all the riding!

The second RCB1000 was ridden by Britons Charlie Williams and Stan Woods, who had chased the Frenchman home in the 1977 endurance series. Honda also had a further 10 factory-supported teams.

“We raced our sit-up bike because it was the only thing we had – for sure, Mr Honda expected

Honda to win!” grins Fujio, who at the time was 30 years old.

By 1978 Yoshimura already had something of a reputation. Pops had learned about engines while flying planes as a flight engineer during the Second World War, then he started tuning street engines for US servicemen during America’s post-war occupation of Japan. In the early 1970s, Yoshimura moved to Los Angeles where he became one of the main men in the nascent superbike scene.

The company achieved its first successes with Kawasaki Z1 engines, then switched to Suzuki’s brand-new GS1000. The Yoshi GS won first time out in March 1978, with Steve McLaughlin taking the laurels in the 50-Mile Daytona Superbike race.

“How come we were successful after only a few months with the engine? Because we had spent so much time tuning Z1 engines and the GS1000 was basically a copy of the Z1” says Fujio.

“Suzuki were definitely more helpful than Honda and Kawasaki, who both had their own racing teams. We concentrated on engines and only had a small knowledge of suspension, so Suzuki helped us a lot with everything else. They supplied chassis parts and drawings and Kayaba forks and laydown Kayaba shocks. The frame was gusseted but otherwise stock. The brake calipers were also stock, with Harry Hunt aluminium discs from the US.

“Wes Cooley rode for us in the AMA Superbike series, so we asked him to ride for us at the 8 Hours and got him to recommend a co-rider. He instantly came out with Mike Baldwin, who was riding a Moto Guzzi in the US.”

Despite their Daytona success, Pops and Fujio weren’t at all confident about the 8 Hours. Their GS1000, which produced 130hp (97kW) – getting on for double the stock output – could last 50 miles, but could it survive 700?

“We did a lot of work on the engine. We developed and cast a new two-ring piston with one compression ring and one oil ring, instead of the standard two compression and one oil. Pops hand-ported cylinder heads and he hand-ground camshafts; he spent countless hours doing that. And we made our own exhaust and fitted Keihin CR31s, which were the most popular race carbs at that time.

“We had various problems. The engine occasionally broke valve springs on the dyno, so that made us a bit worried. The next thing was the cam-chain slipper, which kept breaking on the dyno. We had never had this problem with the Z1, which used steel rollers at the top of the chain run, so we did some machining and fitted steel rollers. We finished that job right before we left for Suzuka. We figured it would work but we were on a knife edge.

“The people from Suzuki and RK chains were also worried about the final-drive chain. They said it wasn’t designed for 130 horsepower, so RK made four special chains for us; they were the first O-ring chains.

“The biggest problem we had was with the clutch, which had been designed for an 85-horsepower [63kW] engine. At Daytona, Steve’s clutch broke on the cool-off lap, right after the chequered flag! The stock GS had damping springs in the clutch basket and we kept having problems with play between the basket and the primary gear, right up to the day before qualifying at Suzuka. I finally found the problem on the Friday. The rivets that held the clutch basket to the primary gear kept shearing because the damping springs were too weak. Stiffer springs fixed it.

“Me and Pop had lots of fights. He was such a stubborn guy: I would say, let’s do it this way, and he would say, no, let’s do it that way. We used the CR carburettors right up to qualifying because they made lots of power, but they were also very hard to control and used a lot more gas. Wes and Mike complained about the hesitation and so on. We also had 29mm Mikuni smooth-bores, so I swapped to them. They were a lot friendlier for the rider and used 15 per cent less gas, a huge difference. It was the first 8 Hours, so no one really knew how far a tank of gas would go. We were very cautious.

“Even so, we were still not at all confident about the race. We had lots of power but also many problems. We kept hearing stories from other teams: the Yoshimura bike goes fast but it’s not going to last, so we don’t have to worry about them.”

At least Yoshimura had probably the best tyres. “I brought four sets of Goodyear slicks from America as hand-baggage. Kenny Roberts had started doing 500 GPs that year with Goodyear and was winning races, so I talked to the Goodyear guys and told them Suzuka would be important for them. We had one set for qualifying, two sets for the race and one set spare. All the other teams ran treaded front tyres, so we were the only guys with full slicks.”

Of course, running with slicks caused ground-clearance problems, so Yoshimura cut and welded both sides of the crankcases and ran a very small magneto.

Despite all the gremlins, qualifying went well. Cooley and Baldwin ended up second fastest behind a Yamaha TZ750 two-stroke, a popular leftfield choice for endurance racing. Graeme Crosby and Tony Hatton were third on a Yoshi Z1, Léon and Chemarin were fourth and Masahiro Wada and Akihiko Kiyohara were third on a Kawasaki KR350 GP bike. At that time endurance racing was essentially a run-what-you-brung discipline.

The TZ – ridden by American 250 champ David Emde and Isoyo Sugimoto – led the early laps, chased by the KR350, and then Cooley and Croz. Stan Woods went home red-faced after wrecking his RCB on the very first lap.

“The TZ took off, but we knew they had to stop for gas more often. Before halfway we were leading the race, with Emde behind. Léon and Chemarin tried to catch us and dropped a valve, so both RCBs were out.”

When Yoshimura changed tyres after four hours they nearly put themselves out of the race; or at least, Cooley did.

“At that time the riders helped out doing pit work as well. Cooley was changing the front wheel with an impact wrench. It went dagga, dagga, dagga and one of the stub bolts snapped off. So we had a huge problem – we were worried the axle could come out. The riders also knew it could be a big problem! But we couldn’t do anything about it. Luckily, there were two threads left on the bolt, so we could just about put the nut back on. In the next pit stop we ground off part of the nut and bolt, so the nut couldn’t come off.”

And there was more: one of the rear-shock mounts broke at the weld. So Cooley and Baldwin were riding around, waiting for the front wheel to fall out or the rear suspension to fail.

As dusk fell the Yoshimura pit prayed for the bike to hold together. And it did. Cooley took the chequered flag with a four-lap advantage over Emde’s TZ750. Crosby took third, despite running out of fuel at one point.

After the race, Yoshimura discovered they’d been even luckier. “We found that one of the frame down-tubes had broken during the race, but no one had noticed! After that Suzuki fitted rubber-mounted side plates to the production GS1000 engine, so we were already helping them.”

Fujio has no doubt about the importance of their 8 Hours victory.

“I think this event made Yoshimura; that and our 1979 Daytona Superbike win, with Crosby. Even now, with all the racing we’ve done, it’s always dramatic to win, but that race was special because we had so many problems, right up to qualifying.

“We didn’t expect that much of a reaction after the race. We fixed our problems and we won, but all the press and all the guys from Suzuki were saying this is such a huge, huge incident! A bike like this – which looks like a stock streetbike – beat the real endurance bikes made by the Honda factory. So it became big, big news and, sure, Honda didn’t like it!

“We’ve since won three more Suzuka 8 Hours – in 1980, 2007 and 2009 – but the first was definitely the best!”