Cycle News - Archive Issues - 1990's

Riding Tea.... Mof;Or Sporf;!'s '""a....aha FZR750R Going 0 ... in 61yle By Brian (;a tterso n/P h o tos b y Panl (;a......t h e rs f there was one thing tha t became apparent during the 1989 AMA Su perbike road racing seaso n, it was th e disparit y i n eq u i p me n t between co m pe ti ng bra nds. Ducari, Kawas ak i a n d .Suzuki all had more-or -less co mpe titiv e machi nery, tru e, but the AMA's idiosyncra tic regulati ons kept the latest '89 mode ls fr om Yamaha (O WOI) and Honda (R C30) o ut of th e cou ntry. And Yam aha 's FZR 750R, with its roots set in 1987, was looking espe. cia llyoutda ted. Som eon e must hav e forgo tte n to tell T eam Motor Sport's Rich ard Arn ai z th at hi s bike was un competirive, how ever , for he did what man y cons ide red to be im pos sible - he ga ve Yam aha it s fir st Nati onal Su perbike win since Eddi e Law son wo n th e 1986 Daytona' 200. Arn aiz 's feat is even more impressive when you realize that between his and Lawson 's wi ns, a pair of rid ers whowent on to wi n 250cc G Ps - J ohn Koc in ski a nd J immy Fil ice - each spe nt a year o n Yamaha superbi kes, and ca me u p win less. So when T ea m Moto r Sport 's Malcolm Hill i n vit ed Assoc ia te Edi tor Pau l Carru thers a nd. myself to sa m p le Arnaiz's race-winning superbi ke, we thought we kne w wha t to expect. . And to be honest, the prospect d idn't exac tly have us turn ing cartwh eels. Neith er of us are Nati onal ca liber su perbi ke pilots, a nd th e notion of manhandling a nearl y three-year-old pri vateer Yamaha a ro und bumpy, high-speed Willow Sprint:/s International Racewa y was daunting a t best. After all, we'd watched Arnaiz wrestl e with the bik e throughout the season - we kn ew it was a handful. In the end, we were very pleasantly surprised - th ough it didn 't start ou t that way. As I swung a leg over his superbike for the first time, Arnaiz told me to be cautious while scrubbing in the new tires. The bik e's pair of 17-inch magnesium Marvic wheels (3.5-inc h wid e fron t/5.5-in ch rear ) were sh od I 16 with Michelin sficks i-- a radial rea r and bias-pl y fro nt. Arnaiz himself prefers radi al s at both ends, and explained th at he fitted a bias-ply . front for our test sin ce it 's more pred icta ble tha n a radia l '(th us less likel y to resu lt in a journalis tind uced cras h, th ough he didn't say that . ) T he bias/radial combina tio n is not a n u nusual one - in fact , Arnaiz's teammate Phil Kress used this setup on his su perbike all yea r long. "J us t lea n it over a little bit at a . time; o nce you 've dragged yo ur knee a few times th e tires will be alrigh t," Arnaiz said, as th o ugh it were as easy as a wa lk in the park. But first I'd have to get out of th e pit lan e, which in itself took a few a ttemp ts. The dr y clu tch, co up led with the free-revving motor and light flywheel made the bik e a bear to launch . Too much th rott le a nd it made ungodly cha tter ing so unds; too little and it fell flat on its face. With Arnaiz sm irking kn owingly , I go t the combination right a t last and set out on my first exp lora tory laps. The five-valve pe r-cylinder DOHC Gen esis motor with its four, 45degree forwa rd -inclined cylinders · wasn 't nea rly as power fu l as I'd imagined it, in spite of the fact that it 's go t everything bu t the kitchen sink under its skin . "Every thing" mea ns Yamaha's superbi ke race kit , whi ch incl u des 37mm Mi kun i constant -veloci ty dow ndraft carburetors, more radica l ca mshafts, high comp ression pistons, stronge r connecting rods, dry clutch , a nd a o neup, close-ra tio , six-speed "tra nsm issio n. The cylinder heads were po rted by C. R. Axtell, o ne of the count less cont acts Arnaiz ma de du ring his dirt track days. The Kerker four-into-one exha ust system wi th trick, carbo nfiber silencer sounds as good as it looks. As o ne would im agin e with a heavil y-breathed-on 750cc fou r, th e power is concentra ted a t th e top of its range. It likes to be run o ver 8000 rpm , and ac tually felt rather a ne mic ben eath that mark. Despite my initial worries (caused by m y relative inexperi ence with racing slicks), scru bbing th e tires proved to be no problem a nd I was soon circu la ting at a co mfortable pa ce. The Michelins lived up to their reputation , and before long I found myself negotiating turn two (a 1800 . fourth-gear right-hander) faster than I'd ever go ne before - yet it didn 't feel th at way. There was an almost eerie smooth ness in the way th e bike beh aved a t speed, as though it knew it wa s fulfilling its singula r purpose. It was n 't a t all intimidating. In [act, it was easier to ride fast around the race track than a ny of th e sport bik es I'd ridden there previously. Much of its composure stems from its rigid Del ta Box aluminum fram e and swingarrn, as well as its weight - or rather lack th ereof. . • " I tried to lighten it as much as .possible," says Arnaiz. " I had a chromemoly subframe and fairing stay built (saving abo u t four pounds) and I drilled o ut all the little nuts and bolts, but th e AirTech fibergla ss really put th e finishing touch on it. It wa s still five-and-a-h alf or six pounds overweight, and wh en I put the AirTech stuff on it, it was right th ere (a t 1989's 380-pound minimum weight limit - 1990 will see th e lim it lowe red to 370 Ibs.)" Arnaiz's su pe rbike also mak es use of Yamaha 's su perbike chassis kit, with suc h pa rts as 43mm fork s (u p from th e 4 l m m stockers) , ra cing shock (sta mped " O W81" ), shorter and more rigid swinga rm, and tiny . rearset footpegs. If ' Arnaiz 's superb ike had one shortcoming, it was the way the front end pushed. This was especiall y noticeable in turn four (a doubleapex right -h ander with an off'ca mber, downhill exit). On or off tfie gas , it simply didn't want to turn , instead understeering toward the pavement's edge. Arnaiz verified my findings: " T hat was the biggest problem wi th the bike, " he admitted. "The fro nt end really pushed. It bothered mea whole bunch. It seemed like I could get into a comer pretty fast , but I sometimes had problem s getting out because my bike wasn't properly set up." The FZR 's handling is hampered by its co nserva tive stock geometry (ra ke 25.3 degreesltrail 3.94 in ches). Arnaiz experimented with Kosman adjustable-offset triple clamps, but co uld never find a viable so lu tio n: " A cou p le of times I just did what I co uld with the th ing and it kinda reach ed its limits. It 's not like it co m p a res to a H onda RC30 o r some th ing like th at. " (Arnaiz kn ow s the d ifferen ce, havin g ridden an RC30 a t the Suzu ka 8-houL ) My o nly o ther criticism concerned th e lack of feel through the front brak e lever, in sp ite of the steelbraided T elfon lines. Arn aiz said this was unusu al, so we'd di sm iss 'it as a case of air in the li nes. Nevertheless, th e du al four-opposed pi ston Bremb o brak es with floating 320mm front ro tors proved effective stoppe rs. An obliga tory rear brak e is fitt ed wi th a single-pis ton calipe r a nd th e smallest ro tor Arnaiz co uld find. Arnaiz' was the tricker of th e two T eam Motor Sport su perbikes, as Kress' mad e do wi th th e stock forks , brakes a nd fro nt wheel (it did ha ve a M ar vi c rear). It was a bo ut 20 pounds hea vier tha n Amaiz's. Race bikes hav e a rep utatio n for being unreliable, but in 1989 Arnaiz's o nly mech anical problem was a spu n rod bearing. Of co urse, this occurre d a t the wor st possible time - during hi s heat race a t th e fin a l ro und of th e series, which put him on th e last row of th e grid for th e fin al - essent ia lly endi ng his hopes of claiming th e Superbike crown. The fact that Arn aiz was in con tention for the tit le at all, and that he won a t Road America, goes to show tha t wit h so me ca refu l R&D (and above all - a skilled rider), even an essen tia lly "outdated" ma chine has a shot at glory. If there's one thi ng to be said for our ride o n .R ic h a rd Arnaiz' s Yamaha FZR750R superbike, it is that th e experience provided us with a cl ear under standing of wh ere su pe rbikes hav e co me from - if not where they'r e go ing. •

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