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/127546
p lacing the starter behind the cyli nders and above th e cases. Total engine width is 420.5mm, 30.5mm less tha n the 400cc engine in Suzuki's Bandi t, and 68 .5mm na rrower than the GS X600 Katana. The engine is designed to centralize mass and allows it to be pos itioned for op tim um front-to-rear weig ht balance. Placing the cra nks haft low also contri butes to the GSXR 's overall low center of grav ity. Within the engine is a directactivated valve train where the camshaft lobes act directly on the valves, eliminating the need for rocker arms. This design is intended to maintain precise valve timing control, especially at high rpm, and helps reduce weig ht since the rocker arms are elimina ted. A single spring per 25.5mm in take and 22.5mm exha us t valve, and nar ro w valve stems further reduce weigh t. Valve adjustment, maintained by a shim located under th e valv e bu cket, requires more work since the camshafts must be removed, but the maintenance int erval ha s been increased to 7500 mi les. There are on ly four eaIDshaft journals to minimize friction. In o rder to reduce cylinder head and com bus tion chamber size, a narro w 16degree valve angle is used. This also crea tes a straig h ter intake path fro m th e 36mm Mikuni carburetors to th e cylinders for mor e effecie nt cylinder cha rgi ng and combustio n. The intake trac t was a lso straigh tened du e to th e red uced pitch between cyli nder bore cent ers, especially on th e number one and four cylinders. Con necti ng rods wit h bo lt-o n bear ing ca ps, desi gned to red uce load concentration on the big end of the rod, link the pistons to th e forged, onepiece crankshaft that rides in 34m m journals. The crown of each piston is trea ted with Alumite to i ncrease durability, while the underside of the piston crowns are cooled by oi l spray similar to other GSXRs an d the Kata na models. The high-p ressure lubricatio n system is powered by a single-stage oil p ump which is driven by a gear beh ind the primary dri ven gear. That gear also drives the externally mounted wat er pump. The oi l pan is offse t to one side to clea r the fo ur-i n to-two-into-one exhaust system. Oi l jets also provide direct lubrication to key poi nts in the six-speed transmission. The transmission shafts have involute splines designed to provide more load-bearing surface area than conventional splines and . allow the gears to move smoother when shifting. In or der to determine the optimum fra me shape and construction, the G SX R6 00's a l umi nu m fram e was designed by fin ite eleme nt method (FEM) co mputer analysis . Both extruded an d cast aluminum components are used, as they are on the 750 and l lOOmodels, in ma ki ng the frame to add torsional rigidity. Suzuki .claims that the pentagonshaped mai n frame rai ls contribute to much of the fram e's stre ngth. The rear sub-frame is removeab le for easier maintenance. . Rear suspension is hand led by an aluminum swingarm that is ma ted via linkage to a full y-adj ustabl e Showa shock. The righ t side of the swingarm is curved to allo w the sta in less steel muffl er to be tucked in closer. A fu llyadj ustable, 41mm inverted Showa fork is used up front. The fro nt brak es feat ure a pai r of 310mm discs mo unted to the cast al uminum wheel. Sem i-m etallic brake pa ds are mo unted in the staggered diam eter four-piston calipers. The rear (Above) Extruded and cast aluminum frame components were designed using computer analysis. (Ri gh t) A cutaway view reveals the compact engine. (Below right) The 600 is the first water-cooled GSXR. (Belo w) Total engine width is 420.5mm, which is considerably narrower than the Katana 600 motor an d Suzuki's 400cc Bandit engine. brake features a 240mm disc and twopiston caliper. Dun lop radial tires are mounted on cast aluminum rims. According to Suzuki, the enti re pac kage weighs 459 po unds dry. T hat's 52 pound s heavier than the claimed dry weight of its riva l, the Ho nda CBR600. Well , fire 'er up! Yes, the new GSXR600 is a fast motorcycle. Very fast. But you migh t doubt that whe n you first open the throttle, because the ' GSXR600 isn't bu rsting wi th low-end power, but wait a fraction of a secorid for the rpm's to build and wham mo, it takes of£! The first time the GS XR is clicked through the gears, the rid er is immediately rem in ded that this mo tor is designed for the track, a p lace where the need le rarely, if ever, drops below eight grand, especially o n a 600cc motor cycle. So who needs low-end anyway ? Well , lu ckil y, for those who pl an on ow nin g th e GSXR600 and have no intentions of coming near a trac k, it does have enough "gru nt" to be city wort hy. In fact, the GSXR does a comendable job getting the rider from o ne sto p sign to the o ther, wit hout havin g to slip th e cl utc h too much . But it's on th e ope n road or th e race track where the GSXR600 is happy. The power comes alive in the middle of the powerband and really mot or s around 8000 rpm. Even though th e power hi ts prett y hard o n top, the po werba nd is fair ly . smooth and ·ta me. But there's no denying, the GSXR likes to be revved. A lo t. Shifting is extremely po sitiv e. The six -speed tra ns m issio n is very smooth and req ui res only a slig h t nudge on the shiftlever to catc h the nex t gear, with or without th e aid of the clutch. T he GSXR600 is one of the best handlin g sport bikes we' ve ever thrown 29