Cycle News - Archive Issues - 1990's

·D TTR C Kenny Roberts' Yamaha TZ700 IR A K By Dean Adams Photos by Bert Shepard t hap pens, oh, once or twice a year. The p hone w ill ring a t Kenny Roberts' hou se in Mod esto, and on the othe r end of the line will be a determined individual who th rough perse- : vera nce, good intentions or connections has obtained the King 's pri vate number. "They'll say, 'Yeah, I h ave your old race bike: " Robe rts exp lains, "It'll be an o ld d ir t tracke r o r o ne of the ma n y Yamaha road racers. I'll ask them some specific qu estions, wa s the frame broken and rewelded many times by the swi ng arm pivots? Inevitably, after a few questions it b ecom es ap p a rent that they don't have the bike I raced." Besides, Roberts an d fri ends own most of the significa n t b ik es h e h a s piloted. So it was with a callused cynicism th at Roberts h ear d th rou gh th e gra pevine that someone out there had one of his old bikes. But not just any old bike . He claimed to have in his possession Kenny's famed Yamaha TZ700 dirt track machine, the bike that he won the Indy Mile with in 1975, the bike that tried very hard to maim Roberts on several occasions. Ahhh, that bike . For those readers without a degree in motorcycle racing history, or wh o simply weren' t yet born in 75, this is the encapsulate d story: In 1975 Kenny Roberts was having a bear of a time trying to retain his AMA Grand National Championship w hile withstanding a charge from a ma n nam ed Ga ry Scott and his potent factory Ha rley-Davidson. In previous attem p ts at th e championship, Roberts utilized th e standard Yamaha fou r-stroke tw in to run d ow n th e booming Harley-Davidso n XRs and run them down he d id , winning multiple Grand Nationa l Cham pionships when the series still combined both road race and dirt track events. But that success w as not carry ing on in to 1975. The tired design of the Yamaha (that w ith ad ded steam from Jerry Branch and Tim Witha m) began to show its chords, and eve n "The King" in his earl y prime cou ld n't s top the advances of Scott and Harley. Bad luck followed Roberts as well th at season - clu tches that were once infallible roas ted, chains snapped, wi res loose ned and fell off. It was obvio us to all at Yamaha tha t it was time for a new m ach in e. Roberts, h is persona l craftsman Kel Carruthers an d key personne l a t Yamaha sco ure d th e corn ers o f th eir imagi nation to fin d somethi ng th a t would give th em an edge. Wha t they needed was ho rsepower, and lots of it. Hence, a sche me was hatched . Roberts w an ted ho rsepower, so let' s give it to him: Altho ugh none of the key p laye rs realized it at the time, they would prepare a m ach ine th at would put th e fear of God in to the Kin g and add an illustriou s chapte r t o ra cing history . Althou gh there we re grave rese rv ations on many front s when the details of the Carruthers-built Yam aha became kno wn, hesitance did not stop the principles from assembling one Doug Schwerma-designed Ch ampi on dirt I track frame , a leaned -on Yamaha TZ700 engi ne (the very same one Roberts had alrea dy won with at Laguna Seca that year) spewing 100-plus horsepower, and a se t of Goodyear dirt track tires . , Wit h these menacing ingred ients they th rew in the be st fabricatio n skills of Carru thers and then flipped the puree sw itch on the blender. Interestingly, with the aforementioned parts in fro nt of h im, the Australian assembled the machine in just five days. Carru thers and company were not th e on ly ones to experimen t wi th a Jap anese mul ticylind er crad led in a di rt track frame. Alth ough it is not generally known in present da y, ot hers also h ad Yama ha TZ-p ow e r e d dirt tracke rs , in cluding Rick Hocking, Ste ve Baker, Randy Cl ee k and Sk ip Aksland . Bu t th ese men we re not Roberts, n eith er were they assi st ed by Kel Carru the rs. And Er v Kanemo to b uilt Ka w a saki triple-powered mach ines for his riders Gary Nixon, Don Castro and Scott Brelsford ; Kanemoto Kaw asakis were fairly successful, although not at the Na tional level. The tightly wound Kawasa ki, at least when compared with th e bruteforce power of the Yamaha, had a touch softer power curve and less horsepower. Too, the Kanemoto Racing triples shook so badly that Kanemoto mad e plenty of foottrips onto the track to retri eve air fil ters and anything else no t nailed on. Their assum p tions of this bei ng a monster unleashed were confirmed once Carruthers stepped back from it in his sho p. All realized th at the Champion Yamaha was, in essence, overkill. Consequentl y, Carruthers affixed a kill switch to the number-three cy linder. Roberts would push the switc h on the entrance to corners, killing th e spark to tha t cy lin de r in orde r to tam e th e wicked ness of th e machine. In a latenigh t ph one call, Ca r ru the rs asked Robe rts ho w fast h e wanted to go a t Indy. "About 130 sho uld be eno ug h," h e es timate d . Ca r ru thers gea re d ap propriately; Roberts we nt to In d y witho u t ever seei ng the co m ple te d b ike. Once h e arrive d, the crew sat him on the seat and ad ju st ed levers an d th e handlebars. Before the bike took to the track, many thought it too powerful and would not be able to obtain an y traction. Roberts might have been one .of these persons, but he won the first semi, putting his name on the grid sheet for the National. From there, the rest is history. Harley tea mmates Jay Spri ngst een . (then a rook ie) and Corky Keener initially led th e 25-mile m ain qui te easily, playing gra bass and sp rayi ng each other with dirt as th e laps ran down to the black and white. Oh, la-de-da, isn't life grand at the front of the packJay? Yes, dear Corky, dreadful about our chum Roberts having such a bear of a time on that contraption...say, what's thatfrightful noise? Sensing a threat, Keener looked back ve ry late in th e race and saw Robe rts d oin g his p aten te d wate r- through-ascree n-door drive thr ou gh the pack. The sh riek of th e Rob erts TZ700 struck a chord deep within Keener, and he signaled Sp ringsteen with a single index finger that Kenn y, like dea th wi t ha black robe and scythe, was coming for them . Grab-ass time was officially over. Cu r re n t Te am M arlb o r o Rob erts manager Chuck Aksland, then a lad of 11, had begged his grandfather to brin g him back East for this even t as he knew it would be a s co rch e r . He was not disappointed. "I still remember seeing hay scattering in the air as Kenny came out of tum four , Aksland recalls . "I still think it was among the best races I ha ve ever seen...top three easy."

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