Kawasaki Z 400

Old John D. Rockefeller was a supreme realist and as such naturally had little enthusiasm for innovation. He once told an interviewer that pioneering was risky business; the sure-fire way to succeed simply was to copy success. A good plan? It was for Rockefeller, who accumulated a megamillion-dollar fortune back when the shiny new dimes he gravely doled out to importunate widows and orphans still would buy a crust of bread.

Rockefeller's law of applied economics has guided many business decisions, and we now find evidence that it is at work in motorcycling. Saleswise, Honda's CB-350 twin was one of the all-time great motorcycles. At least a half-million of that model were sold in America alone. It was inevitable that people would try to duplicate the CB-350's success by substantially duplicating the motorcycle, and that's what has been done: Honda itself has made a try, with the new CB-360 we tested in our December, 1973, issue; and now Kawasaki has crowded into the act with a new model—the KZ 400.

Kawasaki will not thank us for comparing the KZ 400 with Honda's CB-350, but there are similarities so obvious as to demand comparison, though in fairness to Kawasaki this should not be carried too far. One underlying yet still easily detectable similarity is in intent: ride the KZ 400, even if only around the block, and you'll know it was designed to do things the way the CB-350 did them—but a little faster and better. And far more similarities than differences exist in the appearance of the KZ 400 and CB-350. This last is especially true of the two bikes' engines, which are strikingly alike, right down to their scantily-finned cylinders and primary case shapes.

None of this is to say Kawasaki's KZ 400 actually is a copy of the Honda CB-350. Similarities do exist in terms of appearance and feel; otherwise they are very different motorcycles, as should be expected. Honda's CB-360 proves through its existence that the old CB-350's makers did not consider it good enough for 1974. It is reasonable to assume that Kawasaki also had in mind a successor for the CB-350, and certainly not just a copy.

Kawasaki has worked a general improvement over anything else in the under-400cc street bike class by providing the KZ 400 engine with a Yamaha-style balancer, a contra-rotating counterweight housed in a bulge on the front of the crankcase and driven by a chain reaching back to the crankshaft. This balancer subdues most of the shaking otherwise to be expected from a vertical-twin engine, which is a plus all by itself. But Kawasaki also has taken advantage of the relative freedom from vibration and bolted the KZ 400's engine solidly into its frame. Chassis rigidity and thus stability is served by using the engine as a frame brace—and in the KZ 400 the balancer minimizes the magnitude of the payout in variable-diameter handlebar grips.

For the KZ 400, Kawasaki has produced a frame that doesn't seem to need much assistance from engine bracing. A backbone tube of substantial diameter forms an inherently rigid connection between the steering head and the tubular fork above the swing arm pivot, and the big widely-spaced lugs behind the transmission housing tie very solidly into the pivot supports. There is evidence throughout the structure that Kawasaki's engineers were determined to avoid the flexi-flyer effect in the KZ 400, and Cycle's theorists grudgingly admit that, in all, it's a nice piece of work.

All theory aside, the KZ 400 really does handle pretty well. It's not quite as nimble as the CB-360 with which it inevitably will be compared by buyers, but the KZ 400's handling certainly cannot be termed heavy. Kawasaki has followed closely the current Japanese practice of providing nearly all street machines with a steering head angle, or rake, of 27-degrees and combined that with a longer-than-normal trail of 4.13-inches. This steering geometry combines with the KZ 400's weight distribution to give nicely neutral steering and a straight-line stability that's worth its weight in gyroscopes when you're facing gusty sidewinds or following freeway rain-grooves. We especially liked the steering's neutral feel. Most bikes' front wheels tend either to steer into or out of turns, requiring the rider to hold a little pressure on the bars, and many have steering that changes character with speed. The KZ 400 almost seems to aim itself, and holds its line around turns with commendable precision—as long as the road surface is fairly smooth.

Unfortunately for the KZ 400, things like frame rigidity and the matching of weight with steering geometry are only the foundation for good handling and not the whole package. Before it will handle really well a bike also needs good tires and a suspension system that will keep those tires firmly in contact with the road. And in certain of these areas the KZ 400 is sadly deficient.

The Kawasaki's Yokohama tires seem to be fine, but we can't be sure. The bike's suspension is bad enough to obscure all but the most obvious of tire-performance characterictics. Sporting riders won't be impressed with the Yokohamas because they have very soft carcasses and squirm around a lot under the loads imposed by hard cornering and braking. But those same characteristics lend them an ability to envelop road irregularities, reduce ride harshness, and provide the insensitive rider with enough control feedback to keep him from straying into trouble.

It is good that the KZ 400's tires do not encourage spirited riding, because the bike's suspension lapses into raging protest when it is ridden hard and sometimes even when it isn't. Here again we are confronted with symptoms masking other symptoms: we think the front suspension is inadequately damped but can't be sure, as most of what the fork legs might be doing or failing to do gets obscured by the commotion back at the rear wheel. We do know that a ferocious hopping of the front wheel can be provoked with hard application of the front brake; all else is sicklied o'er with the rear suspension's misbehavior.

Very nearly all that can be said of the KZ 400's rear shocks is that they do provide a convenient strut-mounting for the springs. It must be assumed that the oil inside the damper bodies—if any—is there merely to keep them from squeaking, as the control exerted over wheel movements is so slight as to be undetectable. Somebody in a decision-making slot at Kawasaki clearly has failed to grasp the fundamental difference between "inexpensive" and "cheap." Maybe it will help if we tell them, here, that the KZ 400 is a relatively inexpensive motorcycle taken as a whole, but handicapped by shocks that are overwhelmingly, miserably, abominably and infuriatingly cheap.

Neither were we exactly enchanted with the KZ 400's brakes. By all that's right and holy the front brake should work extremely well, and it's obvious that plenty of thought went into designing the disc and caliper. Most of the bikes from Japan have brake discs made of a stainless alloy steel, which resists rusting but really doesn't help the brake function as a brake. The KZ 400's disc is a one-piece casting and appears to be mostly iron with a bit of nickle to keep down corrosion, and it should function better than a stainless disc. Similarly, the caliper mounting promises much: it is attached to the fork leg through a hall-joint swivel, and there is every reason to expect that this arrangement would allow the pads to pull up squarely against the disc at all times. Finally, there is the caliper itself: a very hefty hunk of metal, and not likely to cause problems by flexing. Yet, although all the brake's various elements seem to be near-perfect, its performance leaves much to be desired—as does that of the drum-type rear brake. In our standard braking test, consisting of three maximum-effort stops from 60 mph, the KZ 400 averaged .815-G. Not bad, but well short of the .9-plus number we get with most disc-braked motorcycles.

One reason for the Kawasaki's relatively poor showing in the braking test was that its response to control input is uneven. Actually, the back brake's response is fairly consistent: nothing much happens when you first dab at the pedal and the brake keeps right on working at the nothing-much level no matter how hard you stomp. At the front brake you get a disconcerting shudder and a soggy response when the lever is squeezed middling-hard but the bike doesn't seem to be in any hurry to stop. So you squeeze harder and harder, and eventually find that there is a point at which braking ceases to lag behind control pressure and begins to gain very fast, progressing straight into lockup if given half a chance.

What the KZ 400 lacks in brake system response it almost compensates with the splendor of its carburetion. It has a pair of Keihin CVB carburetors with 36mm throats, butterfly throttles and a pull-open/pull-shut dual cable connection with the twist grip. These are constant-vacuum instruments much like those first seen on Honda's CB-450, with piston-type vacuum chambers instead of the more widely used and cheaper diaphragms, and they provide wonderfully clean running. There's never a wheeze or stumble.

The only criticism we have is that the engine's response to the first few degrees of twist-grip rotation is awfully sudden, and made worse by lash in the drive train. It is of course very typical of Japanese bikes with CV-type carburetors. Kawasaki's KZ 400 is somewhat less afflicted with the problem than Honda's CB-360 or the Yamaha TX500.

All previous Keihin CV carburetors have had butterfly-type chokes for cold starting. Those on the KZ 400 are equipped with Mikuni-style mixture enrichers, and they probably contribute greatly to one of the Kawasaki's more appealing characteristics, which is its willingness to start no matter how chill the morning. Flip the little "choke" lever, wipe your thumb across the electric-start button, and the engine is running.

The carburetors must contribute to yet another of the KZ 400's attractive traits: its engine's willingness to pull fairly strongly at low speeds. Smallish ports and mild valve timing helps, too, and it all comes together to make a power curve that seems hardly to curve at all. Power rises with revs, but smoothly and evenly, without being wobble-legged down near idle or developing real biceps up at the red-line. It's an agreeable, unobtrusive kind of performance from an agreeable an unobtrusive engine.

Techno-mavens won't find much inside the KZ 400's engine/transmission casings to tickle their sliderule fancies. The crank is carried in plain bearings, four of them, and the connecting rods also have automotive-type inserts. A pair of sprockets located at the crank's center drive chains running forward to the balancer and up between the cylinders to the single overhead camshaft. The valve-actuating rockers pivot on eccentric portions of their individual spindles and valve lash is set by rotating the spindles until the stem-to-rocker clearance is right, then locking them in place by tightening nuts located under the end-caps on the head.

The drive back to the clutch is across a pair of special sprockets, held in place on their splined shafts by circlips, and a Hy-Vo chain. This form of primary drive is more silent than gears, and has proven exceedingly reliable in a similar application on all the Honda (500 and 350) Fours. The Kawasaki KZ 400 probably will have the reliability; there's no doubt about it being mechanically silent. There's very little noise from the primary drive or transmission, and such as there may be gets submerged in the intake honk set off every time the throttles are cranked open.

Kawasaki apparently has assumed that people who buy the KZ 400 will do their own routine maintenance and has arranged things to make such work easy. We've already mentioned the ease with which valve clearances can be set; the same kind of thoughtfulness is evident elsewhere. You don't even have to pull a dip-stick to check the oil level, because there's that small sight-glass on the primary drive cover. A pointer on the rear brake actuating arm gives an instant reading on lining wear and the owner's manual tells you to replace the front brake pads when they have worn down to their stepped base.

The engine has only a single set of ignition points (its pistons move up and clown in unison, and the single twin-lead coil delivers a waste spark on the exhaust stroke) so replacement and adjustment is half as expensive and less than half as time-consuming as is true with twins having 180-degree cranks and two sets of points. The oil filter is underneath the engine/transmission casing but hasn't been made inaccessable by frame members or exhaust pipes. And the rear wheel can be removed without disturbing the drive sprocket, which is a big help when you're trying to fix a flat.

The engine's high-output oil pump is under a cover located right behind the filter housing, and the cover has a cast-on boss that looks ready to be drilled and tapped to take an oil-cooler fitting. We think that's its purpose; we couldn't find anyone at Kawasaki who could enlighten us on the matter. Still, it's an interesting point because our test bike got very warm when flogged hard and might have benefited from having an oil radiator to help it get rid of heat.

According to the experts, people who make full-time use of the headlights on their motorcycles are less likely to be picked off by cars. We'll concede that, but it still is annoying to find that the KZ 400's 35/50-watt headlight is wired right into the ignition circuit, lighting instantly when the key is switched to "ign." It strikes us as another manifestation of creeping Big-Brotherism.

Plastics have become about as inevitable as sunrise, and they are widely used in the KZ 400. The chain guard is a plastic molding, and there's a secondary guard up inside the countershaft sprocket housing that presumably serves to keep a broken chain from wadding up in there and smashing the transmission casing.

The Kawasaki KZ 400 is handsome because it is well-proportioned, and because—all the plastic notwithstanding—it is very well finished. Kawasaki has in years past built a lot of bikes with chrome thinner than the gold vapor-plated on a spaceman's faceshield, trowled-on welds and paint you wouldn't put on a barn. There's none of that present on the KZ 400; the bike looks really good.

Apart from the rear shocks, the things we liked least about the KZ 400 was its handlebar grips. It's understandable that Kawasaki would want their new model to have non-slip grips, but the only way the KZ 400's could be made less likely to slip or less comfortable would be if they were covered with spikes. The grips' ruffles and ridges will get to your hands pretty quickly even through a pair of gloves, which is too bad because the bike is in most other respects very comfortable.

The suspension isn't sufficiently refined to provide a good ride, but the seating position is absolutely first rate. Some of us felt that the seat would be better if it had another couple of inches in width; all who rode the KZ 400 agreed that the seat/pegs/grips relationship was near-perfect.

The relationship between fuel tank capacity and the availability of fuel was, in contrast, rather poor. The owner's manual says the KZ 400's tank holds 3.7 gallons; we filled it right to the brim, let it drain down through the lines into a graduated container, and had to shake the tank for its last drops to get 3.1 after switching to reserve at the 2.7-gallon mark. We think the bike's about a gallon short of having enough fuel for a decent cruising range but then the energy crisis caught everyone by surprise. Actually, just the 3 gallons is enough to take the KZ 400 at least 150 miles. Even our test riders' customary forcefulness over the mountain roads near our office was unable to depress the Kawasaki's mileage below 52 mpg, and a steady 55 mph cruising speed should bring it up close to 60 mpg.

That 60-mpg mileage figure will, for us, remain a theoretical possibility—the KZ 400 was too much fun to ride fast to test for fuel consumption at a steady 55 mph. Bad shocks or not, and even with the braking deficiencies noted, we really enjoyed riding the Kawasaki hard. It is one of the few motorcycles with enough cornering clearance to keep pipes and stands up off the pavement, and even with the wheels blurring up and down on their undamped springs the chassis' fundamental strengths make the bike safe and responsive.

Kawasaki will make much of the KZ 400's engine balancer; people who ride the bike are likely, initially, to feel that the reality doesn't quite live up to the advertising. It's an observable fact that the KZ 400's balancer doesn't lend the bike the glassy smoothness of a Yamaha TX500, but there's enough of a price differential to excuse the Kawasaki its tremors. Also, the KZ 400 is a lot rougher when new than after a few hundred miles have registered on the odometer and the engine parts develop into friends. You'll get a high-frequency buzz cruising faster than 60 mph even after the break-in period; the KZ 400 still is the smoothest thing in its price/displacement category.

Basically the KZ 400 is like Honda's CB-360: an updated replacement for the ultra-popular CB-350, and it's ironic that with both Kawasaki and Honda building a replacement for one of Honda's motorcycles, Kawasaki should have been more successful in capturing, and improving upon, the essence of the original. Take away the Kawasaki KZ 400's wheel hop, firm up its brakes and it would be a terrific motorcycle. With those ailments it's only what its makers seem to have wanted it to be: a better, faster CB-350.

Source Cycle 1974