1976 Kawasaki KZ900 A4

Motorcycle Classics Magazine Review

In 1976, Kawasaki was putting the final touches on its next big-bore challenger, the soon-to-be-released KZ1000. Until then, the top of the line was the KZ900, essentially a dressed up Z1, only better.

Starting in 1967 and working into 1968, Kawasaki was designing “a Super-cruiser, a machine to replace the legendary Vincent HRD of yesteryear.” At least, that’s how Ivan J. Wagar, writing in the October 1972 issue of Cycle World, described the unlikely code-named New York Steak project. Kawasaki’s research indicated the market was hungry for a reliable, large-capacity motorcycle capable of high performance that, when asked, could also be a decent touring machine.

Kawasaki engineers were well underway with a mocked-up machine equipped with a 750cc 4-stroke engine when Honda burst their bubble with the CB750. Work stopped on the project, but Kawasaki picked it up again in 1970 and decided to go ahead with its original plan, which was, Wagar wrote, a big bore bike with “good handling and brakes.” It was to be fast and comfortable “along with low noise and emissions as design criteria.” According to Wagar, Kawasaki engineers were still aiming for a 1972 production target.

Although Kawasaki’s forte was mostly 2-stroke engine development, 4-stroke technology wasn’t new to the company. Kawasaki produced its first 4-stroke, a single-cylinder 148cc motorcycle engine, in 1953. Ten years later, in 1963, Kawasaki absorbed Meguro Works, Japan’s oldest motorcycle maker and manufacturer of a number of 4-stroke engines, and became the Kawasaki Motor Sales Co.

Ben Inamura, an engineer Kawasaki inherited with its acquisition of Meguro, was responsible for engine development. Contemporary press reports indicate he was simply instructed to build an engine “that works,” whatever the engine capacity. Honda’s introduction of the CB750 helped underscore the fact Kawasaki’s new 4-cylinder engine would have to be larger than 750cc. In this case, it was 903cc.

North American testing began in February 1972, and by mid-year Kawasaki finally delivered the code-named New York Steak as the Z1 900. The Z1 became a 1973 model-year machine, and when it was introduced, it was the largest and most powerful 4-cylinder 4-stroke Japanese motorcycle ever built.

Inamura’s 903cc engine featured chain-driven twin overhead cams actuating shim-over-bucket valves. The head had shallow, hemispherical combustion chambers and the flat-top pistons gave a reasonable 8.5:1 compression ratio. With special sintered-alloy exhaust valve seats, the engine could run on lead-free gasoline. The Z1’s crank was pressed together and turned-on roller bearings, while the connecting rods used caged needle bearings. Fuel and air mixed in a bank of four 28mm Mikuni carburetors. The finished engine produced a claimed 82 horsepower at 8,500rpm, delivered to the pavement through a gear primary drive turning a 5-speed gearbox and chain final drive.

The mill went into a double-cradle, single backbone tube frame with a stocky rear swingarm. Up front was a 19-inch spoked wheel with an 11.5-inch disc brake, while an 18-inch spoked wheel with a large 7.9-inch drum brake was at the rear. Not many bikes on the road had the distinctive style of the Z1, with its streamlined front fender and slim gas tank and saddle. The paint was a distinctive Candy Brown and orange or a green and Candy Yellow.

Lifting the seat revealed the battery, a tool kit and the paper element air cleaner. Beneath the left side cover Kawasaki placed a small oil tank to dole out lubricant to the massive 0.75-inch pitch endless (no master link) final drive chain, larger than what Harley-Davidson fit to their Electra Glide. Overall, the Z1 weighed in at 544.5 pounds wet.

The motorcycle offered

1976 Kawasaki KZ900 A-4 offered here features correct date codes for all date stamped parts and the distinctive green paint is believed to be original. Our vendor has owned the bike since 2018, and has always been keen on regular maintenance, always keeping it clean and “ready to go” (the bike just had the oil changed, and carburettors cleaned, balanced and tuned).  The odometer reads 13,325 miles, which is believed to be genuine, original mileage. Ridden within the last month, this museum quality bike is in great mechanical condition, and is accompanied by original owners manual and full toolkit. Please note, the tires date back to 2001 and it is recommended they are replaced.

Date Codes:

Manufactured 4/76
Rear brake hub torque bar code = 6 3
Key and Lock code = 756
Front brake rotor code = HO
Wheel rim Rear = TAKAS 460 2.15×18 60 305 Japan
Wheel rim Front = TAKAS 460 1.85×19 60 303 Japan
Exhausts = KH1 900 Z1/750 Z2 DGM 30 386 S 76
Swing arm code = 6 03
All dates codes are correct for 1976 KZ900
Parts have not been re-chromed (date and parts code are still sharp)
Original Seat cover
Original Tool kit
Original Manual housed in original sliding tray