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/126792
Kawasakis 1985 GPz600R Ninja By John Ulrich Kawasaki brings Ninja performance and technology to the 600cc class with the new 592cc GPz600R Ninja. The new machine's engine is water-cooled and is narrower, GPZ600R GPz550 shoner and more compact than the GPz550's air-cooled engine, and makes more horsepower. Heart of the GPz600R is the OOHC, four-valves-per-cylinder engine, with bore and stroke of 60x52.4mm and a compression ratio of II: I. Claimed horsepower output is Specifications GPz 600R NINJA Water-cooled DOHC inline-four Bore x Stroke 60x52.4mm Displacement 592cc Compression Ratio ' 11:1 Carburetion (4) 32mm Keihin CV Horsepower 74 bhp @ 10500 rpm Torque 38 lb.-ft. @ 9000 rpm Valves Per Cylinder 4 Intake Valve Size 21.5mm Exhaust Valve Size 1 9mm Intake Life 8.3mm Exhaust Lift 8.3mm Included Valve Angle 36.5° Intake Valve Timing 37°-67° Exhaust Valve Timing 72°-32° (measuring pt.) Omm Ignition Transistorized electronic Lubrication Wet sump Redline 11.000 rpm rpm @ 60 mph 4.700 rpm Gear Ratios . Primary 2.641 Final 2.600 6th 0.851 5th 0.961 4th 1.125 Engine Type (Unit: mm) 34 i- - - - - 4 8 9 - - - - - - l 74 bhp@ 10,500 rpm, with 38Ib.-ft. of torque at 9,000 rpm. Shan, forked rocker arms with adjustablescrew tappets open the valves, twO 21.5mm intakes and two 19mm exhaust for each cylinder; the intake valves are et 19° from vertical, the exha u t valves 17.5° from vertical. The cam run in six bearings machined into the cylinder head casting (the GPz550 ran in five) and are driven off the center of the crankshaft by a link-plate chain. The cam chain differs from previously-seen link-plate chains in that the top and bOllom edges of each link are scalloped to ' reduce weigh t. Measured from and to zero lift, the intake valves open 37° BTDC and close 67° ABOC; the exhausts open 72° BBDC and close 32° ATDC. Intake and exhaust lift are both 8.3mm. The GPz6ooR's crankcases are narrower than the GPz550's, and there's 2mm less distance between the bore centers of cylinders two and three. The alternator is still mounted on the left end of the crankshaft but is much thinner than the 550's, while pUlling out more power; triggers for the transistorized electronic ignition are still located on the right end of the crank· shaft. Alternator and ignition covers are plastic to reduce weight, and the cam cover is secured by just six bolts, with a reusable rubber gasket. The [rant engine mounts have vibrationreducing rubber inserts; the rear mounts are rigid. Overall, the GPz600R engine is 17.9 inches wide, compared to the GPz550' 19.5-inch width. The 600's engine is slightly shorter measured from cam cover to oil sump and is much shaner measured from the front of the cam cover to the rear of the crankcases, 17.7 inches vs. the 550's 19.3 inches. Like the 550, the 600 has a plainbearing crankshaft with five main bearings. There's a link-plate primary chain driving an intermediate shaft; a 28-tooth gear on the end of that shaft drives the 63-tooth clutch. (The GPz550 was geared 26-65; the change, along with a slipper and automatic tensioner on the primary chain, is saic;110 reduce mechanical noise). A cush-drive-style damper is built into the intermediate shaft: the oil and water pumps are driven off the shaft. Each cylinder has its own pressedin iron liner, surrounded by a water 3rd 1.380 2nd 1.777 1st 2.571 Calculated Speed in Gears at Redline 6th 141 mph. 5th 125 mph 4th 107 mph 3rd 87mph 2nd 67mph 1st 47 mph Rake 27° Trail 3.8 in. Front Suspension Type Telescopic forks Fork Tube Diameter 37mm Front Wheel Travel 5.5 in. Rear Suspension Type .. Singleshock swingarm Rear Wheel Travel 5.1 in. Front Brakes DuaI10.6-in. discs Rear Brakes 9.8-in. disc Front Tire 110/90-16 RearTire 130/90-16 Dry Weight 430 Ibs. 56.3 in. Wheelbase 4.8 gal. Fuel Capacity Ground Clearance 5.5 in. 30.3 in. Seat Height Colors Red Retail Price N.A.