Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
Issue link: https://magazine.cyclenews.com/i/127768
(Above)Wes Cooley kept GS-based Suzuki fours In motorcycling's public eye with two AMA National Superblke titles In 1979 and 'SO. Suzuki's GS1100, and later . the Katana, would later hit the s howroom floor to uphold Its performance/mus cle Image on the st reet. (Left) Fredd ie Spencer's AMA Superb lke assault directly Influenced Honda's Super Spo rt lineu p of spo rtbikes in the early 'SOs. Despite Spencer's never having won a Superb ike title for Honda, CB750s, 900s (sh own) and the s ix-cylinder CBX sold well. (Below) Failed co up: Turbo bikes, such as Yamaha's Seca 650, were attempted by all of the Big Four. Overweight and underpowered, they never lived up to the ir expectations. s port bike m ay be t ra ced to th e 1975 Honda CB400F. The smallest four cylind er H onda was a revision of the d ull CB350 fou r, but along the way it took on so me "cafe racer" s tyling cues. While European and especially British owners were modi fyin g their machines to make th em more fu nctional for twisty roa d use, Honda brou ght out the first OEM m achine with lo w bars, rear-set pegs an d a four -into-one exha us t. The CB400F qu ickly developed a cult foll o wing, but lagged in sa les aga inst th e ch eape r but q uicker two -strok e RD 350. By th e t ime th e m od el w as dropped fr om th e H onda lin eup, th e CB4 00F ' s ri di ng p o sit ion h ad be en returned to the old, sit-u p-a nd-beg style. While ,it lacked th e sm oo th good look s of the CB400F, the 1976 Yama ha RD400 continue d Yama ha' s lock on the sm all sp ortbike market. Rem embered . for its cast wh eels fro n t and back , the RD400 offered a refined motor with improved m idran ge performa nce. On ce a production racer had mounted a set of Dunlop's lege ndary K81 tires, their only con cern w as th e od d footpeg a rrangement. For some strange reason, the peg hanger ran under the exhaust system an d was the first th ing to d rag during aggressive cornering. Suzuki jumped in to the four-stroke wars in a big wa y in 1977, the DO HC GS750 refini ng the CB750/Z-1 con cept w ith an im p roved engine a n d lo wer overall weight. Imm ed iately, Yoshim ura turned the GS into a superbike ....-inner, and the arrival of the big brother GSI 000 in 1979 wo ul d on ly im p rove Su zuk i' s ab le, off-the-rack GP racers. Following in th e foo tsteps of the st reet R5, th e "torque induction" RD was a sta ple of prod uction racing, w he re it regu la rly challenged and embarrassed far bigger oppos ition. In 1975 BMW m a d e a hu g e s te p tow ard shak ing off its conservat ive image, prod ucing the R90S twin. Similar to previou s models in terms of gen eral speci fica tions ; the R90S was g ro u n d breaking thanks to its appearance, featuring a handlebar or "b ikini" fairing, bodywork ta il se ct ion and two wild graphic treatments. Th e s ilver- to-oran ge and silver-togrey "fade out" pain t schemes ou traged Beemer purists, but the pa int, together with drilled twin discs and Dell'Orto pump carbs, showed that BMW had joined th e su p e rb ike wars. Soon, th e North American d istributor for BMW had fudged a monoshock track version that race d s uccess fu lly against the AMA-dorninating Kawa saki superbikes. Th e first glimpse of th e modern position as the solid rival to the aging Z1. While Kaw asaki slig h tly revised th e "king" wi th the bigger KZI000 , losing some performance along the way, Suzu ki becam e the privateer mount of choice in four-st roke racing. BMW continued to im p rove th e phys ica l / v isu al n at ure o f the sports mach ine, the Rl 00RS arriving with a full fairing in 1977. Th e enclosed coc kp it, com p le te with low "cl ip-on" bars as standard equipment, indica ted the aerodynamic future of sports/ touring. By 1979, Honda' s bik e image was a stod gy one, the various CB models lagging behind in technical development and most certainly st yling as the "big H" was bu sy establishing a solid hold in the fou r-wh eeled market. So a one-two p unch was required, and Hond a' s big dealer netwo rk was thrilled with the four-valve, four-cylinder CB750F an d four-valve, six-cylind er CBXl000. Basically m odular versions of the same d esign, th e two Honda s were immediate hits, even if the six was a lit- How ever, the CB750 wasn 't just for touring - it qu ickly became popular for all kinds of bike sp orts. The engine in th e relat ively inexpensive Honda was so on putting o u t all ki n ds of ex t ra power, mounted in a hu ge range of specials. Many of today's top tuning companies have their origins in products for the CB750. Even so, the CB750 wa sn 't the performance king of 1969. That honor belongs t o a fa r more agg ress ive be a st , the Kaw asaki HI 500cc tripl e. Quicker than the Honda, th e lightweight tw o-stroke w as not a model of du rability, but its sexy profile and performance attracted a differen t crowd. Unfortunately, the HI was no great handler, partly due to the fact th at themotor wa s offset in the frame to allow the rear drive chain to clear the tire! , The early '7 0s were gre a t ye a rs for Honda, who vi rtu ally controll ed th e motorc ycle market, just as the slow- toreac t British indust ry started d own the drai n. Honda ad d ed th e fou r-cylinder CB500 to the ir stable in 1971, a smaller version of th e 750 th at w as a n inst ant h it . Also, th e no t-pa rticularly-sporty CB350 and CB360 Twins were serio us sales successes, at o ne point gain ing almost a qua rter of total street motorcycle sales -in the U.S. Lots of riders started with a 350, and quickl y moved up to a four. Still, tw o-s tr o kes offere d th e bes t bang for the buck in all-out street perfo rma nce. In 1972, tw o very d ifferent "b u g-fogger" tr iples w ere int ro d uced, succeeding for vas tly diffe rent reasons. Kawasaki refined thei r pe rformance attack with the H2, a machine that some s till say set a sta ndard for power and g ood lo oks . With up s w ept pipe s, aggr ess ive gra phics and a ta il sec tio n ra ther than the regular "bench" seat, the H2 defini tel y a tt ra cte d a yo u ng e r crowd. Handling w as also im p ro ved, although no one would describe any of th e line of Kaw asaki triples (750, 500, 400, 350 and 250cc models) as easy to control at speed. Mea nwh ile, Suzuki launched their GT750 "wa ter buffalo", the flags hip of thei r own th ree-cylinder mod el range. Water-cooled and far more reliable than the Kawasaki, th e Su zuki had a more seda te a p p eara n ce, and quickly won favor as a powerful, touring-oriented mount. In a racing chassis, the eas y to modify GT750 motor was success ful too, even tho ugh tire technology of the da y was not capable of p roviding cons istent grip for a fully-tuned 750cc two-stroke. ' After attracting serious sales with the H2, Kawasaki hit the CB750 righ t wh ere it counted in 1973, when their Z-1 "ki ng' spo rtb ike" w a s introduced. A 900 cc, double-overhead- cam design, the Z-1 w as a big seller th anks to hot perform an ce a n d goo d lo ok s. The CB750 look ed downright s to dgy and British pa rk ed next to the swoopy Z-I, an d Kawasaki's first big four was just as relia ble as H on d a ' s p roven 750 . When police forces started rep lacing thei r H a rle y s wi t h H o n d a and Kawasaki fours, it was clear tha t a mo torcycle revolutio n was taking p lace. . The Z-l was also the next logical step for the aftermarket, jus t as the bike business was com ing to grips with modifying the CB750. These tw o machin es led di rectly to th e form ation of the Superbike class in Cali fornia, w here too much pow er and not enough cha ssis cont ro l produced very exciting racing. Sure, su perbike racin g wasn 't "p roper " in the Grand Prix sty le, but it wa s great fun to watch. Industry peopl e still d e scrib e, in a we, ' watch ing Da v id Aldana trying to hold on to a bucking Yoshimura Z-1 on the banking at Daytona in 1975. Many "real" (read twostroke) racers scoffed at the "Koni s and Ker ker " crowd of superbikers, but the aftermarket nature of fou r-stroke, fourcylinder st reet bike competition led directly to the current American road racing scene. Maybe the 1973 Yamaha RD350 was more appealing to proper bike enth us iast s, since the sm all, two-stroke twin was a direct relative of Yamaha's popular and su ccessful line of widely avail- 13