Retrospective: 1974-1979 Kawasaki KZ400 Twin

1976 Kawasaki KZ400
1976 Kawasaki KZ400D3. Owner: Michael Lane, Kansas City, Kansas.

Nice little bike. Great for commuting, but entirely capable of a cross-country trip. This model was an answer to problems in the global economy. The dollar was devalued in 1971, with President Nixon taking us off the gold standard, meaning we had less money to spend on foreign products. Also, Congress was upping the import tariffs on lots of things, trying to figure out how to pay for the war in Vietnam. In response, Kawasaki decided to build a factory in Lincoln, Nebraska. This was not a real manufacturing facility, but more of an assembly plant, as the import duties on bits and pieces of a motorcycle were a lot less than bringing in a whole one.

1976 Kawasaki KZ400
1976 Kawasaki KZ400.

Kawasaki had been looking at the success of Honda’s little four-stroke twin, the CB350, which had modest performance but all the amenities Americans seemed to like, including an electric starter. Kawasaki’s R&D backroom boys put their heads together, drew up plans and came forth with a very efficient, if rather uninspired, 398cc vertical twin, with a 360-degree crankshaft, an overhead camshaft and an electric leg. In June of 1974 the first KZ400 rolled off the assembly line in Akashi, Japan, and a number of them arrived in the United States. But that was just the beginning, as the factory was turning out a lot more parts than those assembly line workers could use. Crates of them were going to Nebraska. In January of 1975 a KZ400 rolled off the Lincoln line with “Made in the USA” on the ID plate.

One should add that the price of gas went up 45 percent between 1973 and 1975, from 39 cents per gallon to 57 cents. Could there be a better time for a 50-mpg econo-bike to hit the market?

1976 Kawasaki KZ400
1976 Kawasaki KZ400.

The frame was a simple double cradle having dual downtubes, with a big, fat backbone tube meeting up with the cradle at the swingarm pivot, a very solid affair that avoided any notion of flexiness. Front fork was by Kawasaki, very much like a Ceriani, and on the inexpensive, non-adjustable side. Five inches of travel was good, with a 27-degree rake and trail of approximately four inches offering a very middle-of-the-road stance. The swingarm ran out 20 inches, bouncing along on a cheap pair of Kawasaki shock absorbers having preload adjustability and three inches of travel. Too soft, reviewers said.

Spoked wheels were both 18 inchers, the front carrying a 3.25 tire, the rear, 3.50. Braking was done by a single 226mm (10.91-inch) disc on the front, a 180mm (7.09-inch) drum on the back. As a polite reviewer might say, adequate. But this was not intended for sporting riding like the Z-1, and the brakes worked fine for commuter use. Distance between the axles was 53.3 inches.

The wet-sump engine was straightforward, being slightly oversquare with a 64mm bore, 62mm stroke. Of minor note was the chain-driven counter-rotating balancer system down in the crankcase, called “harmonic” by one reviewer. It did not smooth out all vibrations, but for anyone happy to ride at two-thirds of redline (9,000 rpm) it was entirely adequate. Commuters, the intended buyers, were not known as rip-snorting riders.

1976 Kawasaki KZ400
1976 Kawasaki KZ400.

The four valves, two per cylinder, were pushed down by a single overhead camshaft, and 36mm Keihin CV carbs fed high-test gas (preferred) and air into the combustion chambers, where it was compressed 9:1. The engine was rated by the factory at 35 ponies, which was usually measured at the crankshaft, not the rear wheel; on a dyno it was closer to 29. Respectable; good for an honest 90 mph. In 1977, with the fuel crisis in the headlines, the carb size was reduced to 32mm to enhance mileage figures a little. And the compression was raised to 9.4:1, which served to create roughly the same power output. Ignition was by battery and single two-feed coil. Starting was by button, except a kickstarter was there as a backup, as many Americans did not yet fully trust electrically powered gizmos.

1976 Kawasaki KZ400
1976 Kawasaki KZ400.

Primary drive was via a Hy-Vo chain, and then through a wet clutch to a five-speed transmission and chain final drive. The long, flat saddle was great for one person, a bit crowded for two. Looks were OK, with shiny chrome fenders and nice paint on the 3.2-gallon gas tank and side panels. Curb weight was a shade more than 400 pounds. The only complaint seemed to be about occasional oil weepage coming from around the head.

The number of KZ400 models expanded. The D series, the essential KZ400 that we have here, went from ’74 to ’77 and cost $1,170 in ’74. The cheaper S series, with a drum front brake and no electric starter, went for $995 in ’75. And for one year, ’77, there was the A model, with small handlebar fairing, saddlebags and luggage rack.

1976 Kawasaki KZ400
1976 Kawasaki KZ400.

For ’78 the D designation became a B, with a redesign in the head, a slightly different gas tank and mufflers, an extra gear in the transmission and the fuel tap getting a diaphragm. The low-price version stayed with five speeds and had a two-into-one exhaust. And there was the stepped-saddle LTD “custom” model, with cast wheels.

This modest motorcycle was also a modest financial success. Kawasaki ran a lot of entertaining ads focused on the commuter, one saying, “More fun than any car I ever drove.” This ’76 model, in the same family since new, is quite stock except for the MAC mufflers.

For 1980 the engine was bored out to 67.5 mm, a 10 percent increase in size, and received a new KZ440 designation, giving the basic design four more years of life.

10 COMMENTS

  1. I had a 77 model and rode the heck out of it when I joined the Navy. Got me all over the southeastern US of A. In the 2 years I owned it I put 13,000 miles on it. Sold it before I deployed.

  2. I bought one in 1976 when I lived in Ontario. It had the two into one exhaust. Had it for two years. It gave me no problems, however had trouble getting past 70MPH, and was a bit wheezy cruising at highway speed. Had to use the gearshift quite a bit to get the most out of it. Traded it on a 1978 GS550, which was quite an improvement. A very good bike though, very simple and worked well as intended. I should have put a windshield on it, might have been easier to ride at speed.

  3. Bought a ’78 ex demo bike in 1980. Did 35000 miles on it as a tourer/commuter/instructors bike. Sold it to buy a Commando – not the best decision! Saw it later with nearly 90k on the clock. Gave me a great deal of respect for Kawas – have owned mainly their triples & fours ever since.

  4. This bike was riddled with oil leak issues. In 78 dealers were instructed to swap out the head cylinder rods along with all the seals to stop oil from gushing out of the top end. The issue was largely addressed when the 440 came out, but the 400 had developed a reputation by then. Aside from the oil leak, it’s a good bike but in reality it didn’t match up to the cb350 in any way except possibly in the looks category. There are some fun vintage commercials featuring so three models ok YouTube.

  5. Hi I’ve got a 1976 z 400 in real green. All original specification with 9000 miles on the clock.. any ideas how much it’s worth please ? Thanks

  6. I have a 78 B model with 11000 miles
    It sat ten years and needed a tank and carbs. But i used a rust remover and cleaner then an epoxy sealer inthe tank and replaced the CV carbs with the non CV tipe and single split cable.
    I look forward to many miles of enjoyment here in Wa State.

  7. I had a 1979 or 1980 KZ400 Standard. I bought a kit (Felpro head gasket plus the Kawasaki oil-rings) to solve the cylinder head oil leak issue before having an oil leak issue. Before making the repair, I consulted with a Kawasaki Mechanic and slightly increased the torque on the head bolts – zero oil leaks or other issues. The longest trip I took on it was from New Brunswick, Canada to Chattanooga, Tennessee. I put about 10,000 miles on it then sold it for what I paid for it. It was a very good bike for the money.

  8. In 2008, I bought a used 77 A luxury model, out of state of Michigan with the fairing and everything. It’s a reliable and everyday iron horse!
    It does have oil leak, speed not reaching 70 mph issues. I wonder if changing a larger wheel sprocket could improve the speed…
    Last week, the speedometer plate broke due to hi-speed vibrations and aging..,I guess, it’s a 42 year old iron horse.
    Over all, it’s a reliable bike, alway start on the first ouch on the button, a honey-do bike, and probably a good collections.

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