Cycle News - Archive Issues - 1990's

FIRST RIDE SPORTBIKE By Pa ul Ca rruthers Ph otos by Tom Riles LECASTELLET, FRANCE, 0Cf.17-18 r-, 0\ 0\ .... ... ..0 :: Lf) ' ClJ ClJ ;> o z 10 he e ngi nee r ing co ncep t for th e new Kawasaki 7..X-9R was sim ple enough: Take th e existing 7..X-9 and throw it in the trash . Oka y, keep the name - fur old time>' sake. Wh il e s i m p ly gi v in g th e N in ja a makeo ver and placing it on a di et may have sufficed, it was n't enough to sa risfy th e e ngineers a t Kawasa k i. They wanted more. The bike had to be lighter, it ha d to be more powerf ul, it had to handle better... an d it had to be compact. Not even a s ta r va tio n diet wou ld accomplish the changes they' d penciled in , so th ey wiped th e sla te clean an d started from scratch, TI,e result: the 1998 Kawasaki 7..X-9R an d its credo - "New Generation Supersports." And if you still don't think the boys at the Big K were serious a bo ut the newest N inja, try this on for size: "This Is not a sports tou rer,"says chassis des igner Yoshinobo Yamamoto. "This is a racer replica ," Not surprisingly, Ka wasaki elected to i n troduce its new 7..X-9R to the world 's motorcycli ng p r~ss at a race track. Not just any race track, but one with history , prestige, notoriety... and a very long bac k straigbt - tbe Circuit Pau l Ricard in the south of Fra nce, w ith its world-ren owned Mistral Straigh t. With a goal of ge tt ing more po w er, less weight and a decrease in its overall si ze, Kawa sa ki w ent to wo r k on red esigning the 899cc in-line four - from the insid e out . And wh at they ended up with more close ly resem bles the 7..X-6R than the old 900. The ligh ter crankshaft 1998 Kawasaki ZX·9R Totally redone tor 1998the Kawasaki ZX-9R Ninj a. Not content just to do a makeover on the existing mode l, Kawasaki opted to start from scratch when des igning the newes t 900. now measures in at 133mm 0 4m m narrower than the B-m otor t ha t w a s i ntr n > duced in 1994) and 58m m (12mm sho rter than the old mo tor) while th e cyli nderhea d size an d weig h t has been reduced by rep lacing the ra m fo llowers wit h direct va lve actuation . A m o re oversqua re bore x stroke (75 x 50.9mm compared to 73 x 53 .7mm on the old mo tor) allows for larger valve> (u p 1mm in d iame ter to 30mm an d 26 mm ) a nd a narrower valve angle (intake 12 degrees, exhaust 13 degrees). The redesigned powerplant also gets straighter intake ports for improved flow. To fu r the r red u ce weight, the engine cases were thickness-balanced. The new engine also gets the trendy plug-moun ted s tick coi ls that further re duce weig ht while elimina ting the space ta ke n up by conven tional coils a nd w ires (sa vi ng a lmos t 16 o u nces) . Kawasaki also claims that the coils help the bike gain high-rpm performance, as spark-d ro po u t rate has been virtually elim ina ted a nd hig h-rpm co mbus tion efficiency is improved. Kawasa ki has also replaced its chaindriven alternator (located behind the cy li n d e rs o n th e ol d mo to r) w i th a cra nk-m o un ted generator, a unit that Kawasaki claims provides the needed o u tput wi thout co m prom ising crankshaft len gth. Magnesium is also used on the en g in e covers to help in weight red uction. The 7..X-9R's 40mm carbs are abo fitte d wit h the com p a ny's K-T RIC (Kawasaki Throttle Res po nsive Ignition Control) th rottle-position se nsor. Th e sensor, loca ted on the rig ht end of the carburetor-throttle shaft, allows the ign ition timing to be se t base d o n both e ng in e rpm a n d lo ad - improvin g res po nse a t th rottle openings between one-eighth and one-quarter. The sensor also senses opening speed so that wh en the throttle is o pene d quickly in th e middle and upper rpm ranges, igni tion timing is fur ther advanced. to im prove acce le r a tio n . In a n effo rt to ri d th e e n g i ne of a ny d etonation, K-TRI C retards ignition tinting if the throttle is opened more than one-q ua rter between 800 and 1500 rpm. The en d result of all that tech no-babble is a three-dimensiona l timing curve desig ned to provid e quicker throttle response and im proved fuel efficiency a t any engi ne speed. T he clutch has also been r ed o ne , u s in g th e same-si ze plates as those fou nd in the 7..X-6R. In a d d ition, the five -s pri ng clutch eli mi nates the back torque lim iter, a nd cable-cl utch actuation r epla ces the hyd raulic uni t - fo r reduced weigh t, na tu ra lly. As far as the six-speed tran sm ission goes, the sha ft now feat ures involut ed s p lines and a 14mm-s horter d istance betw een the input and outp ut sh af ts, allowi ng for a sho rter engine design. The thing tha t stand s out the mos t when you first see the 7..X-9R is its titanium exhaust canister. Tho se markets with

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