Cycle News - Archive Issues - 1990's

daily life. The balance might begin to tip in the YZF's favor. Maybe... THE TRACK First things first. We know these are street bikes. We know that most of you who buy one of these four motorcycles will be using it on the street - exclusively. But - despite vocal protests to the contrary from at least one manufacturer - these bikes are designed to be capable racing platforms and, because of existing AMA Supersport rules, have to go a long way toward satisfying this requirement to be competitive. It also means that we have to test them to within an inch of their lives - and ours! - on the race track. It's a shame, we know, but if we don't do it, who will? For this we went to Las Vegas Motor Speedway, one of the premier racing facilities in the country. Aside from being geographically attractive for us (and an easy pitch to the manufacturers: "Out of the office for a few days in Vegas? I think we 'can arrange that!"), the Speedway is attractive for testing because of the variety of corners and speeds that it offers in AMA National form; that is, in 2.48-mile-per-lap, banking-pius-infield layout. Of particular use are the two high-speed sweepers that lead out onto. the banking, putting the chassis under a consistent heavy load near max lean, just about tapped in fourth gear. The ability to accelerate all tl;1e way through redline in sixth gear comes courtesy of the long front straight past start/finish, which naturally also gives a good indication of high-speed stability. Braking for the chicane and infield are both done from near top speed - a good test for outright power and feel at the limit of adhesion, as well as of the bike's stability under such a load - while the infield gives you an excellent sense of feel and feedback at lighter lever pressures as you trail brake to adjust your speed approaching an apex. It is als~ very safe. And fun. The track's biggest fault for testing purposes - if yaH can call it a fault - is its smoothness., Vegas is a track that will reward a motorcycle with firm damping rates, which is something to keep in mind when yOli read this portion of the test. To ensure that the bikes were on equal footing, each machine was equipped with Michelin Race 3 supersport-compound DOT tires, graciously supplied by Michelin and mounted and balanced on site by Dale Kieffer of Racer's Edge. It is important to note the front tires - available only in l20/70ZR17 - aren't the manufacturers' recommended size for three bikes of four. The Honda, Yamaha and.Kawasaki all use a 60-series aspect ratio (shorter sidewall) as stock rubber. This will, in theory, tend to slow the steering characteristics and slightly alter the front-end feel of the bike. The extra grip provided, however, more tllan outweighs the very small change in feel, and removes one more variable in the testing process. Simply put, this is a race track, and race rubber is appropriate. Interestingly enough, it is the GSX-R that comes fitted with the "right" tire size. That much would be expected from the bike that is most clearly geared toward prowess on the race track. For that well-timed confrontation with your favored staff rival, there was no other choice. Hop aboard, fold your legs in half to get your feet on the pegs, ignore the lean spot just off idle and get your- kept the revs up over about 9500 rpm. From there to 12,500 rpm is the best of the GSX-R's power, with acceleration tapering off as you approached the 13;500-rpm red line. The peaky power and soft midrange meant you had to work the gearbox to get the best of the quick-revving four, but it is totally up to the task and didn't miss a shift all day.. Braking, aside from a slightly mushyfeeling lever, was tops in this group. Feel at the limit was very good, as was initial bite and ease of modulation - if you were going to pass somebody on the brakes, this was the bike to do it with. Especially if the guy you wanted to get past was riding the Kawasaki. Despite being the only bike equipped with six-piston front brakes, the ZX-6R's stopping power was less than we expected. The strong initial bite of the other bikes in this test gave you the confidel'lJCe you needed to leave your braking to the last possible moment, but that confidence just wasn't there on the green machine. Aftermarket pads should improve this measurably. It's a shame about the brakes, too, because if there is one bike in this test that absolutely needs to be stopped, it's the Kawasaki. Why? This motor flat screams, so much 'so that tester Jason Black remarked that this engine "feels like a 750 when compared to the others." Could it be that we were entering the corners faster? Probably. Jetting is absolutely perfect, throttle response immediate and controllable. Just the right amount of power can be dialed in to suit your needs, whether it is to settle the bike midcorner or to spin up the rear a bit on exit. Midrange power is very strong and at anything Engine Valve vear Bo.. " stroke Displacament Comp....lon ratio Carbumion Liquid-cooled in-line four DOHC. 4 valves per cyl. 66 x 43.8mm 599cc 11.8:1 (4) Mikuni BDSR36R Liquid-cooled in-line four DOHC. 4 valves per cyl. 65.5 x 44.5mm 599cc 12.0:1 (4) Mikuni BDSR36 Liquid-cooled in-line four DOHC. 4 valves per cyl. 62 x 49.6mm 599cc 12.0:1 (4) Keihin CVKD36 Ignition TCBI wi 'di9ital advance and TPS/K-TRIC 91.4@ 12.100 rpm 42.7 ft.-lb. @ 9600 rpm 6-speed Twin~spar aluminum 55.1 in . Di9ital CDI Di9ital TCI 90.0 @ 11.200 rpm 45.0 @ 9200 rpm 6-speed TWin~spar aluminum 54.5 in. 84.3@ 11.750 rpm 43.6 @ 9500 rpm 6-speed Twin-spar steel 55.7 in. Horsepower Torque Transmission Frame Wheelbase Rakeltrail Seat height Suspension Front Rear Liquid-cooled in-line four DOHC. 4 valves per .cyl. 65 x 45.2mm 599cc 12.0:1 (4) 36mm slanted flat-slide CV Computer-controlled di9ital wi 3-D map 89.0 @ 11.200 rpm 42.8 ft.-lb. @ 10.200 6-speed Twin-spar steel . 55.3 in. self out into the heat of battle. Wait for your adversary to come around. Let him lead. Then begin your play. Show a wheel here and there. First under brakes for the chicane. Then at the apex of the sweeping comer that leads to the _short, ll5-mph infield straight. Care to pass under power? Dive up the inside on one of the sweepers that leads out onto the banking. The Suzuki will accommodate you. There is little to stand in the way of setting your best possible lap time. It is these games that illuminate the best quality of the GSX-R in the race track environment: flexibility. Don't misunderstand - you need to be precise - but it is a bike that lets you select or change your line at will, brake with confidence at tlle last possible moment, crank it over that last little bit to tighten your line as you begin to drift wide under power at the exit of one of the two medium-speed sweepers in the infield. Total front-end precision with brilliant feedback, and the finest stock race-track tool you can get in this class. Period. All it asks of you is one thing: Go as fast as you possibly can at all times. Because if you don't put 100 percent of your focus on that, your mind will begin to wander to your cramping thighs, the nonexistent midrange, slippery footpegs (every tester noticed - ends need to be serrated) or poor throttle response exacerbated by excessive driveline lash as you get back in the gas to settle the bike for a corner. The real low side of this is that most low-sides occur preciseLy at that moment: leaned over and off the gas. That hesitation prolongs the time you spend there. The first thing we'd do is re-jet this bike. As it was, once you were in the throttle, things were good as long as you 25.2°/94mm 23.5°/91mm 24°/96mm 25°/96.5mm 31.9 in. 31.9 in. 32.7 in. 31,7 in. 41 mm HMAS cartridge fork wi 5.1-in. travel; fully adjustable Sin91e shock. HMAS Pro-Link rising-rate linkage wi 4.7-in. travel; fully adjustable 46mm cartridge fork wi 4.7-in. travel; fully adjustable Sin91e shock. Uni-Track risin9-rate linkage wi adjustable ride height. 5.4-in. travel; fully adjustable 45mm cartridge fork wi 4.7-in. travel; fully adjustable Sin91e shock. risin9-rate linkage wi 5.2-in. travel; fully adjustable 41 mm cartridge fork wi 5.1-in. travel; fully adjustable Single shock. rislng·rate linkage wi 4.7-in. travel; fully adjustable .120/6oZR 17 radial 160160ZR 17 radial 120/60ZR 17 radial 170/60ZR 17 radial 120170ZR 17 radial 180155ZR 17 radial 120/60ZR 17 radial 160/60ZR17 radial ~ Dual 298mm discs 0\ 0\ Tires Front Rear Brakes Front Rear Dry weight. Fuel capacity Price Dual 296mm discs wi two-piston calipers Single 220mm disc wi single-piston caliper 405.6 lb. 4.5 gal. $7799 Dual 300mm discs wi six-piston calipers Single 220mm disc wi single-piston caliper 388.1 lb. 4.8 gal. $7999 Dual 320mm discs wi four-piston calipers Single 220mm disc wi two-piston caliper 384 lb. 4.8 gal. $7799 wi four-piston calipers ~. 00 .- Single 245mm disc wi single-piston caliper 4121b. \D' 5.0 gal. ;E $7399 >-. (\l 27

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