ENGINE ROOM

With the chassis gurus at Kawasaki holding the trump cards, the engine team, lead by Tomohiro Kanazawa, got busy on a totally new, scratch baked 998cc powerplant. They came up with a super-compact 76mm bore 55mm stroke engine with a combined cylinder and upper crankcase assembly, and used a stacked "tri-axis" transmission crankshaft layout and piggybacked the generator behind the clutch. Kawasaki was able to optimize the overall center of gravity on the ZX-10R by using the over-the-engine frame design and ultra-compact motor and the resulting freedom in positioning of the major components.

After being fed air by the wicked central Ram Air duct and swirling through the frame, past a compact air cleaner and flow-analyzed airbox, a reception is waiting in the form of 43mm Mikuni throttle bodies with dual butterfly throttle valves. Fine atomizing injectors squirt a 70 micron mist of fuel into the intake tract. All Kawasaki says is that flow-analysis was used to obtain idealized intake and exhaust port dimensions. After sifting through the tables covered with a dis-assembled ZX-10R powerplant I was pleasantly surprised holding the cylinder head. Very small looking ports for a motor with a claimed 184 horsepower in real top speed conditions, smaller appearance than the ports on the heads of a mid-nineties Muzzy 750cc Superbike head, this I can tell you. The ports all but shout 'high-velocity' and point towards the recent gains made in cylinder head design. 31 mm intake valves opened by billet camshafts with soft-nitrided lobes let the fuel mixture by, then are slammed shut by single valve springs wound from oval section wire held captive by sintered aluminum retainers acting on 4.5mm valve stems, all elements combining to keep the cylinder head compact and lightweight.

Forged 76mm flat top pistons pumping in plated cylinders compress the fuel mixture to a claimed 12.7 to 1 ratio and the mix is ignited by iridium spark plugs and high voltage stick coils. Spent gases exit with a shove through the titanium 25.5mm exhaust valve into the exhaust plumbing. The ZX-10R has a full titanium system, from the head pipes to the tip of the muffler, the pipes and the internals are all titanium. An aluminum covering surrounds the outer surface of the muffler. A butterfly valve in the exhaust is designed to provide a step-less power delivery all through the rpm range. Kawasaki's' KLEEN system uses a honeycomb catalyze fitted inside the muffler to breeze through current environmental emissions standards.

Kawasaki was a pioneer in the development of the Superbike slipper clutch and the ZX-10R sports the latest incarnation which is currently being described as an 'adjustable back torque limiter' but to you and me, it's a slipper clutch. And it is connected to track-ready close-ratio 6-speed transmission with a 17 tooth countershaft sprocket and a 39 tooth sprocket on the rear wheel.