Kawasaki KZ400

A 1978 KZ400-C1

The Kawasaki Z/KZ400 is a street motorcycle produced by Kawasaki between 1974 and 1984. It was developed into a larger brother, the Z/KZ440 where the stroke was lengthened to increase engine capacity.

Twins

The "original" Kawasaki KZ400 was a 398 cc twin cylinder motorcycle produced from 1974 to 1984, though some later models displaced 440 cc. The KZ400 was built at plants in Akashi, Japan and Lincoln, Nebraska. The Lincoln plant (built in 1974) made Kawasaki the first foreign motorcycle manufacturer to operate a plant in the United States. The KZ400 outsold Honda in the 400 cc twins market through the 1970s. These motorcycles were marketed as fuel efficient transportation; a 1975 magazine advertisement for Kawasaki featured the KZ400 next to a Volkswagen Beetle with the tag line "Think even smaller."

Early models were prone to oil leaks and unstable idling. Both the carburetors and the design of the oil passages were redesigned beginning in 1977. Some models were offered as bare-bones transportation, with no electric start and front drum brakes. Most, however, had a single disc in the front and drum in the rear as well as electric and kick starters. Deluxe models also had a fairing and saddle bags.

Fours

The Kawasaki KZ400 had an inline four cylinder variant named the Kawasaki KZ400-J, which had a slightly different engine derived from the larger Kawasaki Z500/Z550 models. The KZ400J was produced from 1980-1983, and was available in a "West Germany" version limited to 25 kW. The engine was an air-cooled four-cylinder, four-stroke, eight-valve DOHC engine, accompanied by a six-speed gearbox. These bikes were electric start only, and the KZ400-J had a single (US model) or double (UK, Western Germany models) disc brake at the front, and a drum brake rear.

The 1980 model was identified as Kawasaki KZ400-J1, while in 1981 the Kawasaki KZ400-J2 was introduced with small differences, like a transistorised ignition system.

Engine datasheet

	KZ400-J
Bore and Stroke	64.0 x 62.0 mm
Displacement	399 cc
Compression ratio	9.5
Engine oil	3.0L of SE class SAE 10W40, 10W50, 20W40 or 20W50
Cyl. numbering	LTR 1-2-3-4
Ignition pattern	1-2-4-3
Spark plugs	NGK D8EA or ND X24ES-U

Transmission data

	KZ400-J
1st gear	2.57 (36/14)
2nd gear	1.78 (32/18)
3rd gear	1.38 (29/21)
4th gear	1.13 (27/24)
5th gear	0.96 (25/26)
6th gear	0.85 (23/27)
Primary red. ratio	3.28 (27/23*67/24)
Final red. ratio	2.50 (40/16)
Overall drive ratio	6.98 (Top Gear)