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/127180
cs . 00 ~ Suzuki GSX750 Katana (left) and GSXR1100 (right) occupy 'opposit e ends of the sport bike spectrum - sport-tour,:rversus racer-replica. A hush fell over Suzuki's design 'foom."as the orders came down from management. " O u r goal is to build.two new motorcycles' for the 1989 model yea r," stated th e marketing analyst. " A literclass sport bi ke to replace the aging GSXRIIOO and a mid. d lew e i g ht sport-to urer to bridge th e gap betw een th e 600 and II OOcc Katanas." The many tech n o lo gy-h u n gry draftsmen let u p a cheer , eac h anxious to co m me nce crea ting hi s dream design. But their dr eams soon begot nightmares, as the ever-p resent accountant quick ly added, " O h, a nd use existing parts." "Arrrgg~h!! ! " . ' Faced wi th th ese design para meters, many an engineer wou ld run and hide in his soft-walled cubicle , bury hi s head in the CAD /CAM Digest swimsuit issu e and reem erge around lu nch time. But th e boys in Suzuki's ba ck rooms faced the chaln ge h ead -on, a nd went ab out 'co m bin ing th e best of both worlds to p roduce a pair of th e most purposeful motorcycles avail ab le today. , The new GSXRllOO / 60 Suzuki 's race-bred GSXR seri es was unveil ed in 1985, b ut it was '86 before any were available in America. The following years wer e good to Suzuki, as GSX R750s and 1I00s dominated the rac e tracks and showroom floors. However, by la te '87: they were loo king a bit da ted. So the '88 GSXR 750) received numero us u pda tes, particularly in tlie handling department. A stronger alum inum alloy chassis, larger diameter forks, in credible new brakes a nd smaller diameter 17-inch wh eels were the significan t changes, but somehow none of these appeared on th e 750's big-bore breath ren. . For 1989, Hamamatsu needed a new sporting flagship , and went about it in the most practical and perhap s frugal manner - by j ug- glin~ exis ting parts, rat~ e.r th an creating new .ones. Com~mmg the better-h and!mg c h a ss is of the GSXR750 with the mo re powerful engine of th e big-bore Katana gave Suzuki an a ll -ne w GSXR lIOO. And though the price of th e new Suzook has risen to a loft y $6599 (largely due to th e weak American do llar), the cost savings permitted by raiding th e stockroo m have been passed o n to th e purchaser - the GSXR sells for nearly $1000 less th an its ch ief riva l, the Yam aha FZRIOOO. . The simplest wa y to p rod uce more horsepower is to in crease displacement,: so 'the 1127cc Kat an a motor wa s su bs ti tu ted for th e GSXR 's original 1052cc unit. But the Kata na 's lazy, torquey power characteristi cs don't su it a pure sp ort bike lik e th e GSXR, and some ch an ges were required. Th e m aj or e ngi n e differ en ces revolve a ro und th e clutch, ca rbs a nd exhaust. For starters, a hydr aulicallyope ra ted , diaphragm -sp rin g cl u tch replaces the co il-spring u rn t fo u nd on the Katana. The p urpose o f this is to increase pressure aga ins t th e clutch pl at es to better cope with th e increased horsepow er withou t slippage. How ev er, th e di aphragm spring giv es a different feel at th e lever than a coil unit which requires some getting used to. Lever pu ll is stiff initially but softer near the grip, and seems to work best if you trea t it lik e a ligh t switch - on or off. Two-millimeter la rger Mikun i "Slingshot" carb ure tors now introdu ce fuel to th e hungry powerplant, while a corro sio n-resistant , stainless steel, four-into-tw o exha us t system expe nds the burnt gases. A new curved o il cooler permits a larger surface area without interfering with the front tire . Other more subtle ch anges incl ude a steel p la te over the cam ch a in tunnel to str ength en the cylinder head and a stronger bottom end and con necting rods. The primary and fina l-dr ive ratios were a lso changed from th e Kata na 's, and straigh t-cut gears replace the Kata na 's helical-cut pi eces. . On the ch a ssis s-ide, a lo n ger swingarm leng thens th e wheelbase for be tter hi gh-speed stabili ty, whi le a n eight-millimeter lo nger Kaya ba shock absorber "with a sevenmi llim eter lower u p p er mo u nt i ncr ea ses cornering clea ra nce. Rebound damping is adjustable four ways , and preload is sim ilarly adj ustable. We left th e rear suspension stock from day one and "never had a grr pe, Up Iro nt , th e a ll- new 43mm Kayab a cartridge forks have eigh t settings for rebound damping an d 10 for compression dam p ing, although th e screw -type adj usters loca ted at . the top and bo tto m of the for ks ha ve 12 positions (or "clicks"). A preloa dadj usting co llar is also fitted. Running th e damping at and around the minimum settings and wi th the preload set in the middle gaveus the best results. If you're lik e us you 'll soo n fin d yourself carrying a stu bby screwdriver in your jacket pocket just . to pl ay with the forks at sto plig hts . A steering dam per is fitted, but does little more than provide convenient mounting poin ts for an a fter market u nit. Nissin four-opposed piston fro nt " brakes are simila r to th ose used on th e 750 , b u t th e full y-fl o a ti n g 310 mm dual discs are solid, ra ther than dri lled , " and are also th icker than th e 750's. T he same 270 mm rear disc fitted to the '90 is used at the rear of the I 100. Other identical pa rts to the 750's