Cycle World - - Makers - By KEVIN CAMERON / Pho­tog­ra­phy by DREW RUIZ

For all of us in Amer­i­can road rac­ing in the 1970s, Kel Car­ruthers was the man who al­ways found a way. When Kenny Roberts went to Europe in 1978, it was with Car­ruthers as tech chief. Three suc­ces­sive 500cc World Cham­pi­onships were the re­sult.

Break­ing into Aus­tralian rac­ing as a teenager on home-built ma­chin­ery, Car­ruthers made him­self the one to whom Honda en­trusted a replica RC161 four-cylin­der 250 Grand Prix bike. That was a ma­chine no­to­ri­ous for weave dur­ing cor­ner exit, but Car­ruthers dis­cov­ered that if he stayed down and pushed the ma­chine up, ac­cel­er­a­tion be­came sta­ble.

Five years at the Aus­tralian top made Euro­pean Grand Prix rac­ing the next step. With his wife Jan—ever a force to be reck­oned with—and his dad, Car­ruthers was ready for the GPS. They were quite dif­fer­ent from to­day’s Mo­togp and its con­tracted rid­ers. To get start­ing money from the many race or­ga­niz­ers, you needed a strong rep­u­ta­tion. To make ends meet, you needed start­ing money from as many classes as you could pre­pare ma­chines for. Mul­ti­ple care­fully worded let­ters on sta­tionery pre­sent­ing your lat­est ac­com­plish­ments had to be mailed out ev­ery week to race or­ga­niz­ers, and re­lent­less use made of what is now called “net­work­ing.” Push hard enough to be­come known, tem­pered by the ab­so­lute need to be on the grid at the next event. Car­ruthers did not once go to the hos­pi­tal in all his years of rac­ing.

“We didn’t make much money, but we were do­ing the things we liked to do,” he said.

He be­came 250cc World Cham­pion in 1969 on a fac­tory Benelli four-cylin­der—win­ning the Light­weight TT at the Isle of Man along the way and hold­ing the fast-im­prov­ing pack of pro­duc­tion­based Yamaha TD2 two-stroke twins at bay.

An­other year was enough, and with an of­fer to race in the sud­denly ex­plod­ing U.S. AMA se­ries, he was away. Teamed with the late Don Vesco, Car­ruthers ex­panded his skills

to in­clude two-strokes. “Vesco had a crude lit­tle dyno. I built a sin­gle­cylin­der test en­gine and just started find­ing out stuff. And my last year in Europe, I’d been on Yama­has.”

That rig en­abled him to greatly boost the TR2’S power by ex­tend­ing its sec­ondary trans­fers all the way down to the crank­case (as on the 250 TD2), leav­ing so lit­tle seal­ing sur­face that he had to run cop­per base gas­kets. He also moved the 350’s en­gine for­ward to im­prove sta­bil­ity.

He won the U.S. AMA 250cc ti­tle and gave Yamaha its first-ever big class win, beat­ing all the 750cc four-strokes at Road At­lanta on the light 350cc twin. Yamaha U.S. signed him for 1972—not only to ride, but also to be men­tor to the emerg­ing Kenny Roberts.

What hap­pened next made his rid­ing al­most in­ci­den­tal: Car­ruthers was good at find­ing ways to get the best from Yama­has, so when the four-cylin­der TZ750A was de­vel­oped along with a sim­i­lar 500cc GP bike, Car­ruthers—now man­ager of Yamaha’s U.S. race team—was sum­moned to Ja­pan to eval­u­ate it. It weaved at high speed. Car­ruthers fixed it with a longer swingarm.

In the hands of Gi­a­como Agos­tini, the new four-cylin­der won Day­tona at the first try (1974), but its pipes, made into flat­tened ovals to fit un­der the frame, blew to pieces dur­ing the race. Car­ruthers had al­ready built the an­swer: round pipes, routed three un­der the en­gine and one across be­hind the four car­bu­re­tors. They were put into pro­duc­tion. The man be­hind some of rac­ing’s most impressive dy­nas­ties, Car­ruthers’ suc­cess came from prac­ti­cal ex­pe­ri­ence.

When Roberts fa­mously won the AMA’S Indy Mile in 1975 on a Tz750-pow­ered dirt-tracker, Car­ruthers was builder and tuner.

When a Kawasaki KR-250 set pole for the 1976 Day­tona 250cc race, Car­ruthers al­most ca­su­ally raised the ex­haust ports and short­ened the pipes 20mm on Roberts’ Yamaha. The Kawasaki threat melted away.

At Tal­ladega in 1974, Don Cas­tro’s fac­tory 750A threw his feet right off the pegs past start-fin­ish; the weave was back. All Satur­day morn­ing, Car­ruthers had the bikes up on work stands with their front ends off. When they went back to­gether, they went straight; he’d found a prob­lem with a lo­cat­ing clip.

At a later break­fast af­ter the race (an­other Yamaha 1-2-3), he said: “With 750s, it looks like we’ll need to put just as much work into chas­sis as into en­gines. If not more.”

So it turned out as Roberts went to Europe to race 500cc GP two-strokes. Mo­togp en­gines have be­come just black boxes, while chas­sis re­main the cen­ter of devel­op­ment.

Yamaha could de­sign and man­u­fac­ture, but they needed a track­side en­gi­neer who could solve prob­lems in the mo­ment—not make a study and pub­lish a re­port in six months. In 1969, Car­ruthers and his Benelli took the Light­weight 250 tro­phy at the Isle of Man. In 1971, he would turn his at­ten­tion to­ward the AMA.

In Europe with Roberts, Car­ruthers con­tin­ued to do things that would have got­ten Yamaha’s most se­nior en­gi­neers fired: When Yamaha fielded its 150-horse­power 0W-54 square-four in 1981, Roberts said: “It feels like it’s run­ning on three. If this is what we have to race, we may as well go home now.”

Car­ruthers mea­sured the en­gine and saw Yamaha had given in to their usual temp­ta­tion: mak­ing the trans­fer ports too high (which takes revs off the top).

“We had a lit­tle lathe in the trans­porter, so I made a setup and ma­chined a mil­lime­ter off the base of the cylin­ders,” Car­ruthers said. “Then I raised the ex­haust ports a mil­lime­ter.”

The en­gine was trans­formed. Roberts won the next race— Hock­en­heim in Ger­many. In an­other sea­son, when a chas­sis needed a steer­ing-head an­gle out­side its range of ad­just­ment, Car­ruthers sawed it off the bike, changed the an­gle, and welded it back on. He had the cer­tainty of prac­ti­cal ex­pe­ri­ence: You do what the sit­u­a­tion tells you to do. When lap­tops ar­rived, he pro­voked much frown­ing among the en­gi­neers by mak­ing a spread­sheet for test re­sults, tap­ping in all the data as it was gath­ered. Af­ter a year he was told, “OK, you can use.”

He had be­come rac­ing’s in­dis­pens­able man.

“Kel-san, please fix” be­came a com­mon re­sponse to track­side prob­lems. But Yamaha was learn­ing rapidly through the 1980s, such that one day Car­ruthers sur­prised us all by say­ing, “I’m just a parts changer now.”

In ad­di­tion to the three 500cc world cham­pi­onships with Roberts, he’d also tuned him to a pair of Grand Na­tional Cham­pi­onships in 1973-’74 and a For­mula 750 cham­pi­onship in 1977. He was crew chief for Ed­die Lawson’s 500cc world cham­pi­onships in 1984, ’86, and ’88, and Wayne Rainey’s three cham­pi­onships 1990-’92.

His last year as a GP team tech man­ager was 1995. The years fol­low­ing found him applying his two-stroke un­der­stand­ing to per­sonal wa­ter­craft rac­ing and to mo­tocross with much suc­cess.

He is 80 well-lived, cre­ative years old this year.

“Kel-san, please fix” be­came a com­mon re­sponse to track­side prob­lems.

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