Pop Yoshimura was in at the start of the ’70s su­per­bike boom, tun­ing the hell out of Suzukis with his bare hands. Here’s how he es­tab­lished his leg­endary name


The life, times and un­par­al­leled skills of the man be­hind Yoshimura’s suc­cess

Hideo ‘Pop’ Yoshimura be­came the world’s most fa­mous mo­tor­cy­cle en­gine tuner as the di­rect re­sult of a near-fa­tal air crash. The teenaged Yoshimura was drafted into the Ja­pa­nese mil­i­tary dur­ing the early days of World War II and was near­ing the end of his fighter-pi­lot train­ing when the ac­ci­dent hap­pened.

“My father wanted to be a fighter pi­lot, had passed all the tests and was ready to go,” says his son Fu­jio. “But then at the end of his train­ing his plane had an en­gine fail­ure, so he had to jump – but his para­chute didn’t open un­til just be­fore he hit the ground, it barely saved his life. He was dis­charged from the navy pi­lot school be­cause he had lung dam­age, but his dream was still to fly air­planes, so he be­came a flight en­gi­neer. He stud­ied four-stroke gaso­line en­gines, like the Zero fighter en­gine, from the bot­tom to the top.

“Af­ter the war there were a lot of mo­tor­cy­cles run­ning around, so he be­came in­ter­ested in them and started work­ing on en­gines. He had stud­ied en­gines so closely dur­ing the war that there were no com­peti­tors with half his ex­pe­ri­ence. He had so many crazy ideas and could chal­lenge so many things, all by him­self.” Many of the mo­tor­cy­cles run­ning around Ja­pan were rid­den by some of the 300,000 Amer­i­can ser­vice­men who oc­cu­pied the coun­try from 1945-52. Pop es­tab­lished his first, tiny shop near a USAF air­base, where the dol­lar-rich Amer­i­cans bought bikes and asked Pop to make them go faster. He soon be­came the go-to en­gine tuner and founded Yoshimura Mo­tors in 1954, a year be­fore Suzuki even launched its first proper mo­tor­cy­cle.

Yoshimura gained its first lau­rels with Honda ma­chin­ery. In 1964 a Yoshimura-tuned CB77 won the Suzuka 18 Hours race (yes, 18 hours, not eight). How­ever, Yoshimura wasn’t quite ready for the big time. The in­creas­ing dom­i­na­tion of two-stroke race bikes kept things quiet, un­til Honda un­leashed its CB750 in 1968 and Kawasaki its Z1 four years later.

Fi­nally, Pop could go to work. In 1971 a Yoshimura CB750 led the Day­tona 200, un­til it broke a cam-chain. In the USA the su­per­bike revo­lu­tion was go and Yoshimura’s renown spread across the coun­try. Pop knew a golden op­por­tu­nity when he saw one, so in 1973 he moved to Los An­ge­les where he es­tab­lished Yoshimura Rac­ing, which later be­came Yoshimura Re­search & De­vel­op­ment of Amer­ica.

Nei­ther Pop nor Fu­jio got out much. Father and son spent end­less days and nights in the dyno room and work­shop, Pop grind­ing camshafts by hand while young Fu­jio looked and learned. “Af­ter the CB750 we ran Kawasaki Z1s for a while,” adds Fu­jio, who be­came com­pany pres­i­dent a few years be­fore his father died in 1995. “We got lots of horse­power out of them, but they wob­bled so much we were just scratch­ing our heads – what could we do? Then Suzuki came out with the GS750. We dis­cov­ered this mo­tor­cy­cle in late 1976. That’s when we knew – wow, Suzuki are se­ri­ous!”

Not long af­ter that Suzuki’s top four-stroke en­gi­neer Et­suo Yok­ouchi vis­ited Suzuki Amer­ica in LA. Yok­ouchi was the mas­ter­mind be­hind the GS750, Suzuki’s first four-stroke, and its big brother, the GS1000. “We were very lucky,” re­calls Fu­jio. “One day


we made a call to Suzuki Amer­ica and he was there; it was kind of a co­in­ci­dence. We made an ap­point­ment, had a face-to face-meet­ing and made a ver­bal agree­ment, look­ing into each other’s eyes and went from there. In those days that was good enough.” Suzuki wanted Yoshimura to help them go rac­ing with the GS750 and the soon-to-be-launched GS1000, be­cause although Suzuki had just won their first 500cc world cham­pi­onship with the RG500 two-stroke, they knew lit­tle about go­ing rac­ing with four-strokes.

The new part­ner­ship was an im­me­di­ate suc­cess. Yoshimura GS1000S won the 1978 Day­tona su­per­bike race, took first place in the first-ever Suzuka 8 Hours, mo­nop­o­lised the podium of the 1979 Day­tona su­per­bike race and won the 1979 US su­per­bike cham­pi­onship. Su­per­bikes were big news for the first time; Honda Amer­ica en­tered the class in 1980 with Fred­die Spencer, and Yoshimura im­ported fac­tory Suzuki rider Graeme Crosby for the Day­tona su­per­bike race. Croz won the race from the back of the grid, af­ter he had in­fringed a mi­nor rule in his heat race.

These were the Wild West days of su­per­bike rac­ing, when en­gi­neers and me­chan­ics trans­formed in­nocu­ous street bikes like the GS1000 into tyre-shred­ding mon­sters. These trans­mo­gri­fi­ca­tions weren’t easy to bring about, re­quir­ing end­less hours of en­gine tun­ing and chas­sis re­designs. “We had a lot of fun with the old road bikes be­cause there were so many ar­eas we could put our ideas into,” says Fu­jio. “To me, the 1980s was the peak. There was so much en­gi­neer­ing go­ing on back at the shop, be­cause af­ter ev­ery race we needed to do some­thing dif­fer­ent for the next race.”

Don Sakakura, who joined Yoshimura R&D Amer­ica in 1980, also re­mem­bers those mad days and nights with fond­ness. “It was a re­ally neat ex­pe­ri­ence,” says Sakakura, who is still with the com­pany. “We learned many dif­fer­ent crafts and skills be­cause we were con­vert­ing what were al­most tour­ing mo­tor­cy­cles into mo­tor­cy­cles that could go around a race track. We were look­ing for lev­els of en­gine per­for­mance and dura­bil­ity that the bikes weren’t de­signed for. That forced us not only to find more horse­power but also find weak points. When we dis­cov­ered weak points it was hard work to make sure they didn’t af­fect the way the bike went around the track, which got us think­ing a lot more.

“It was en­joy­able, be­ing deep, deep into those ar­eas: hands-on grind­ing, weld­ing, bend­ing, what­ever you had to do to get the job done. They were skills I was taught by Pop, Fu­jio and Sue­hiro Watan­abe [who be­came head of Yoshimura in the US when Pop re­tired and Fu­jio

re­turned home to run Yoshimura in Ja­pan]. I’ll never for­get the camshaft de­vel­op­ment and the ideas that Pop had – file in hand, grind­ing a cam from bil­let and pro­fil­ing the cam to a spec he liked!”

And it wasn’t just frame tubes that Yoshimura and their Amer­i­can ri­vals at Honda and Kawasaki were bend­ing. US su­per­bike reg­u­la­tions de­mand stan­dard frames, but the show­room frames of that time were dan­ger­ously un­fit for pur­pose, es­pe­cially when it came to re­sist­ing the huge loads im­posed by hurtling around the Day­tona bank­ing at 170mph. All the teams had no choice but to bend the rules by us­ing replica frames fab­ri­cated from stronger, higher-qual­ity tub­ing. They were all at it and the scru­ti­neers turned a blind eye. Yoshimura came to dom­i­nate ev­ery­thing. In 1981 Wes Coo­ley and Crosby rode their GS1000S su­per­bikes – Fu­jio’s all-time favourite – to a one-two at Day­tona, then Crosby used a Yoshi-pow­ered fac­tory Suzuki TTF1 bike to win the Isle of Man Clas­sic and F1 TTS. Two years later a Yoshi Suzuki TTF1 bike won the Suzuka 8 Hours and the en­durance world cham­pi­onship, with Richard Hu­bin and Herve Moineau on board. While Pop and Fu­jio did the en­gines, Suzuki looked af­ter the TTF1 chas­sis, which was based on the RG500.

There wasn’t much that Pop and Fu­jio didn’t do to the

dohc 16-valve GS1000 en­gine to make it so dom­i­nant: highly pol­ished cylin­der head, forged pis­tons, ex­ot­i­cally-timed cams, spe­cial crank­shaft, en­larged valves, lighter tap­pets, ti­ta­nium valve-spring caps, 31mm Kei­hin smooth-bore carbs, Koku­san CDI ig­ni­tion and so on. The re­sult? From 100bhp at 8700rpm to 150bhp at 10,500rpm.

But the father/son part­ner­ship wasn’t all peace, light and race vic­to­ries. “Pop had god hands, but he also had his ideas and I had mine!” Fu­jio re­calls. “We had a big fight dur­ing the first Suzuka 8 Hours. We were hav­ing so many prob­lems with the clutch, but he had his way of fix­ing it and I had mine. We had a big fight! I was ready to go back to the States. Then Wes Coo­ley came up and said: ‘Please stay, we’ve got qual­i­fy­ing in two hours!’” As the 1980s eco­nomic boom got un­der­way, bike sales rock­eted in the US and Ja­pan, en­gorg­ing fac­tory su­per­bike bud­gets. Suzuki couldn’t af­ford to keep up with Honda, Kawasaki and then Yamaha, who came to dom­i­nate Yoshimura’s two big­gest races of the year: Day­tona and Suzuka.

But all that changed with the launch of ar­guably the first real su­per­bike: the GSX-R750, which ar­rived in the US af­ter it was launched in Europe in 1985. “Prior to that we were rac­ing the GSX750 [with young punk Kevin Sch­wantz on­board], which was more of a street ma­chine that we had to mod­ify our­selves be­cause the fac­tory wasn’t that in­volved,” adds Sakakura. “The first GSX-R was a ground-breaker. We had come from the GS750, the GS1000 and the GSX750 and then all of a sud­den, wow, we’ve got a su­per-light alu­minium chas­sis and a su­per-pow­er­ful en­gine. The power-to-weight ra­tio was in­cred­i­ble, so it was re­ally more of a race ma­chine, not like the street mo­tor­cy­cles we’d had be­fore. For me, the GSX-R was the most im­por­tant stage in learn­ing about rac­ing – and that’s when the Suzuki fac­tory be­came se­ri­ous about rac­ing, so the as­so­ci­a­tion be­tween Suzuki glob­ally and Yoshimura be­came very strong, plus the en­gage­ment be­tween Suzuki Amer­ica and Suzuki Ja­pan be­came very ac­tive.”

Although Honda had un­leashed their in­cred­i­ble RC30 World Su­per­bike ho­molo­ga­tion spe­cial three years af­ter the GSX-R750’S Euro­pean launch, Yoshimura had one of its best years in 1989. Jamie James won the US Su­per­bike crown aboard the lat­est GSX-R and Doug Polen took the All-ja­pan TTF1 and TTF3 ti­tles aboard a Yoshi-pow­ered GSX-R750 and GSX-R400. That year’s 8 Hours en­gine, a 749.7cc unit, pro­duced 140bhp at 13,500rpm, while the 756.2cc US su­per­bike en­gine made 143bhp at the same revs.

Yoshimura Suzukis have won all kinds of races and cham­pi­onships around the world, but the com­pany’s year al­ways re­volves around two main events: Day­tona and the Suzuka 8 Hours. “The 8 Hours is my favourite race,” says Fu­jio. “In Ja­pan we spend most of our time and ef­fort on the 8 Hours be­cause we must get a good re­sult. The rea­son we do the All-ja­pan Su­per­bike Cham­pi­onship is to de­velop our 8 Hours bike!”

Fu­jio re­mains heav­ily in­volved in the firm, but misses the good old days. “Back in the early 1980s, all you needed to go rac­ing was a rider, a few me­chan­ics and a team man­ager, whereas now I need five or six peo­ple to run one god­dam mo­tor­cy­cle!” he laughs. “Ev­ery­thing is so spe­cialised: tyres, elec­tron­ics, en­gines, chas­sis and so on. This can mean that the sat­is­fac­tion you per­son­ally get from rac­ing is less, be­cause your re­spon­si­bil­ity is di­vided by five or six be­cause that’s how many peo­ple you need to run the mo­tor­cy­cle.”


Pop en­joys a ciggy in the pits while he and Wes Coo­ley pre­pare to smoke their ri­vals on track

Graeme Crosby on a Yoshi GS1000S holds off Hon­damounted Fred­die Spencer on his way to win­ning at Day­tona in 1980

The Suzuki Team at Suzuka in 1979. Left to Right: Ron Pierce, Pop Yoshimura and Wes Coo­ley

Coo­ley and Fu­jio Yoshimura (stars and stripes cap) at Day­tona in 1979. when Yoshi took a podium clean-sweep

Crosby on his way to win­ning at Day­tona in 1980. His GS has the same ex­haust as the TTF1 bike

ABOVE: Pop port­ing a cylin­der head. Get­ting stuck in with grind­ing, weld­ing and bend­ing metal was all part of the deal

LEFT: Young up­start Kevin Sch­wantz on a Yoshimura Suzuki GSX-R750 at the 1985 Suzuka 8 Hour

ABOVE: Pop and Fu­jio tend to their GS1000 en­durance bike on the eve of the 1978 Bol d’or 24 hours. Riders Wes Coo­ley and Ron Pierce suf­fered an ex­pired en­gine on the Sun­day morn­ing

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