Mid-Size Commuter Bike: 1974-1979 Kawasaki KZ400

A profile of the Kawasaki KZ400 and its contenders.


| March/April 2015


1974-1979 Kawasaki KZ400
Claimed power: 35hp @ 8,500rpm
Top speed: 93mph (period test)
Engine: 399cc air-cooled SOHC parallel twin
Weight: 399lb (wet)
Fuel capacity/MPG: 50-60mpg
Price then/now: $1,170 (1974)/$750-$1,500

Just as Kawasaki aimed the 1973 Z1 squarely at Honda’s CB750, they also tried to out-Honda Honda in 1974 with the KZ400, their take on the best-selling CB350. As with the Z1, they leapfrogged Honda with more capacity, but stopped short of upping the ante further by giving their new little KZ400 the Z1’s dual camshafts. Why?

The answer may be the intended purpose of the KZ400. While the 903cc Z1 threw down the performance gauntlet, the mid-size KZ400 twin was designed as an economical, easy-to-ride, unintimidating commuter bike — and it arrived just in time for the 1973 oil crisis. Under an Arab embargo, the price of crude oil rose fourfold between October 1973 and March 1974. Suddenly, fuel consumption became really important.

Delivering around 60mpg, the KZ400 was certainly economical, and it would also comfortably keep up with traffic, especially at the then mandatory maximum 55mph highway speed. And while a 15-second quarter-mile time wasn’t exactly blistering, it would leave all but the most muscular gas-guzzling cars sitting at the stop sign. But was the KZ400 just a bigger-inch CB350 clone?



The KZ400 engine used mildly over-square dimensions of 64mm bore and 62mm stroke for 399cc. The 360-degree crank (the CB’s was a 180-degree) ran on four plain main bearings with a manually adjustable central chain driving the single overhead camshaft, which operated the four valves by rockers on eccentrics. (Rotating the rocker spindles allowed for valve adjustment.) And while the 360 crank produced smoother power pulses, just like British twins, the format invited vibration. Kawasaki fixed this in the 400 with maintenance free, chain-driven balance shafts. Lubrication was wet sump and ignition by a single contact breaker with a dual-output coil firing both cylinders.

A pair of 36mm Keihin CV carburetors fed the two cylinders, which exhausted with the aide of an equalizer chamber cast into the head. Drive to the wet multiplate clutch and 5-speed transmission was by Hy-Vo chain, with 530 chain final drive. The powerplant was installed in a conventional but solidly built mild steel tube frame with a telescopic fork and a twin-shock swingarm rear end. Brakes were a single floating two-pot caliper disc front and single-leading-shoe drum rear. Equipment included electric start (with kickstart backup), external gear position indicator, crankcase oil level sight glass, and a warning light for a blown stoplight bulb, as well as separate tachometer and speedometer with trip meter.

jim
3/10/2015 7:10:48 PM

I find it amazing you left out the Suzuki GS-400 built I think from 1976 to 1981. I have owned all three of the 400s you mention plus the Suzuki. I was also a motorcycle mechanics instructor at the time teaching a Honda supported program in the public school system and have done major work on all four. The DOHC Suzuki was substantially better than all of the three you profile in handling, braking and speed. The Honda being the only one coming any where near it in terms of performance. None of them had the build quality of the Suzuki especially the Kawasaki and Yamaha which to me felt shoddy and cheap by comparison. I still have one modified as a cafe racer and love it. Jim Reed Vero Beach, FL


jim
3/10/2015 7:09:23 PM

I find it amazing you left out the Suzuki GS-400 built I think from 1976 to 1981. I have owned all three of the 400s you mention plus the Suzuki. I was also a motorcycle mechanics instructor at the time teaching a Honda supported program in the public school system and have done major work on all four. The DOHC Suzuki was substantially better than all of the three you profile in handling, braking and speed. The Honda being the only one coming any where near it in terms of performance. None of them had the build quality of the Suzuki especially the Kawasaki and Yamaha which to me felt shoddy and cheap by comparison. I still have one modified as a cafe racer and love it. Jim Reed Vero Beach, FL








Ride 'Em, Don't Hide 'Em Getaway

Classic Motorcycle Touring and Events.


The latest classic motorcycle events and tours.

LEARN MORE









The sound and the fury: celebrate the machines that changed the world!

Motorcycle Classics JulAug 16Motorcycle Classics is America's premier magazine for collectors and enthusiasts, dreamers and restorers, newcomers and life long motorheads who love the sound and the beauty of classic bikes. Every issue  delivers exciting and evocative articles and photographs of the most brilliant, unusual and popular motorcycles ever made!

Save Even More Money with our RALLY-RATE plan!

Pay now with a credit card and take advantage of our RALLY-RATE automatic renewal savings plan. You save an additional $4.95 and get 6 issues of Motorcycle Classics for only $24.95 (USA only).

Or, Bill Me Later and I'll pay just $29.95 for a one year subscription!




Facebook Pinterest Instagram YouTube Twitter

Free Product Information Classifieds


Copyright 2018, All Rights Reserved
Ogden Publications, Inc., 1503 SW 42nd St., Topeka, Kansas 66609-1265