Cycle News - Archive Issues - 1980's

Ninja 600R comes in two color schemes: Red and white with blue tank top (shown); and red and black with a silver tank top. -------------------------------our recent tech analysis (Cycle News, October 24), is smaller, shorter, '1arrower and lighter than the GPz550 engine. But we've learned more since that tech story was published. We knew the 600R makes more power than the GPz550. Now we find that there are some interchangeable parts, such as the transmission assembly an,d the clutch. But to reduce the strain on the clutch, Kawasaki engineers changed the primary ratio; the intermediate shaft between the crankshaft and clutch now has a 28-tooth gear vs. the GPz550's 26-tooth gear; the Ninja 6ooR's clutch basket has 63 teeth vs. the 5OO's 65 teeth. That means the ratio between the intermediate shaft and the clutch is reduced from 2.5:1 to 2.25:1, reducing the torque multiplication between the crankshaft and clutch but increasing the speed at which the transmission shafts spins. (Changes in final drive gearing compensate for the primary gearing changes.) Because the transmission spins faster, the engineers added bushings to the third and fourth gears on the counters haft, which run steel-to-steel in the 550 transmission. The men from Kawasaki also spent considerable time in a wind tunnel testing fairing designs; the one the inja 600R ended up with is smooth in the headlight area and has ducts on both sides. The new hape, and especially the ducts and the shape of the lower fairing, greatly im prove air flow through the radiator compared to the Ninja 900. According to Kawasaki engineers, hot air stagnated behind the inja 9OO'radiator, contributing to the machine's tendency to run hot. But the Ninja 6ooR's fairing draws hot air out from behind the radiator and is the single most significant factor in the model's improved cooling compared to the Ninja 900. No doubt that wind tunnel testing influenced the size, shape and positioning of the mirrors on the 600R; and like the mirrors on the Ninja 900, they're essentially useless for determining what's tagging along in the bike's slipstream. To see behind, the rider must take one hand off the bars and pull the arm in; otherwise the view to the rear is limited to close inspections of jacket sleeves. More wind hits the rider's helmet on the 600, compared to the 900. And the 600R has rubber froDt en 'ne mounts to reduce vibration, instead of the 9OO's dynamic balancer shaft. Redline is 11,000 rpm, and claimed peak horsepower is 74 bhp at 10,500 rpm. The 6OO's fork stanchion tubes are larger in diameter - 37mm - than the 35mm tubes found on the GPz550, but the tubing wall thiclrness is reduced from 4mm to 3mm in the interest of saving weight. And whilt the 600R has larger front discs (10.6 inches vs. the 550's 10.2 inches) it has a smaller rear disc (9.8 inches vs. 10.2 inches). Most obvious in any comparison, the 600R has smaller wheels than the GPz550. The 6ooR's wheels are Enkei cast aluminum aIloy, an MT2.50-16 front and an MT3.oo-16 rear. Both carry new-design Ounlops wi th wraparound tread, a 110/90-16 K825A front and a 130/90-16 K825 rear, both Vrated. There's good reason the 600R feels small and cramped, racebike-like. Those rearset pegs? They're 14.6 inclies off the pavement. The seat is 29.9 inches off the ground, measured with the bike tanding on its wheels, unladen. Dry weight is 430 pounds, making wet weight about 470 pounds with a full gas tank. The feel is sporting; there's no doubt about the 6ooR's purpose. The high pegs and short bars are not the most comfortable on the freeway; but for riding fast around corners on a twisty road or race track they're perfect. 0600 can be as quick as a 900, but riddeJ:! through the mountains in the company of a Ninja 900, the 600R acquitted itself well. Ground lost on straight sections was made up - and more - getting deep into and quickly around corners. The 600R turns easily and has excellent brakes and corneringclearance. Its ability to change direction quickly makes it possible for a rider to accelerate out of a tight turn harder in to a series of esses. The Ninja 600R makes its best power above 8000 r~m, but will happily churn along at legal speeds on city roads and highways at 4000 rpm. Engine'speed at60 mph is just below 5000 rpm. The only distraction at slower speeds is slightly notchy shifting. It's more of the same at the road racing track. It's there that the 600R 's brakes really make their mark: They're the best stock brakes on any street bike. The smaller r r . . .. Kawa..ki's Ninja 600R has outstanding cornering clearance; dragging the fairing while the bike is still on two wheels isn't possible. Get off those brakesl The key to long life and happiness on a Ninja 600R is to keep on the gas into and through the corners. controllable and predictable, and the 600 has none of the 900's tendency to lock or chatter the rear tire goi ng into corners. The fronts don't fade even in repeated hard use and are very strong. The 600R is stable in corners, fast and slow. either end breaks loose, and its nimbleness is a big asset in tighter turns. Much of the 600R's willingne s to change direction has to do with the 16-inch front wheel; at first the bike seems almost flighty. As the rider gets u ed to the bike and its quick handling, his lap times drop and drop and drop again. At the most a hard rider will drag the ti p of a foot peg; at Firebird International Raceway we dragged the right peg but not the left. But there's a price to be paid for everything, and the price the 600R extracts for its easy turning is the same that every motorcycle with a 16-. inch front wheel demands: A modification of riding technique at or near the limits qf cornering. The rider must finish his braking, get into the turn and dial on the throttle; backing off the gas at or approaching the apex, even a notch, loads' the front wheel and makes it push. Which, in too many cases, means the front end turns in and the rider crashes on the Racers who pioneered the use of l6-inch front wheels learned thatlesson long ago; now that street bikes follow racebikes and come with 16inchers up front, the lesson must be learned by anybody who wants to ride their 16-inch-equippedSlreetbike hard. How fast is the 600R? In a demonstration at Firebird, Jay Glea on got one to turn the quarter mile in 11.82 seconds and 112.50 mph. Members of the press present also had a chance to ride examples of the bike, but without the same advantages Gleason enjoyed. Glea on made his run in sets of six; press men were allowed three passes, racing against each other, the passes roughly 40 minutes apart and notalways on the same bike. The best motojournalist's time was 12.40 seconds at I08 mph: my best pa s was 12.41 seconds at 108 mph. Given the chance to run in at least sets of three runs, given the chance to drain excess gasoline from .the tank and perhaps adj ust rear tire pressure,·. several journalists probably could go 12'.0 seconds and 109 mph on a 600R. As it stands, the inja 600R will be a tough bike to beat in its class on the basis of power and handling - as~uming t~e use of the proper co~~er-

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