Letter From Japan
LETTER FROM Japan
Riding Kawasaki’s ZX-4
Kawasaki’s ZX-4 is a good news/bad news machine. The good news is for Japanese motorcyclists: Unlike previous Kawasaki GPz and Ninja 400s, the ZX-4 was designed exclusively to be a 400. That makes it smaller and lighter than its predecessors, which were built around 600cc-size engine cases. But that's the bad news for American motorcyclists: The ZX-4 is not the harbringer of a ZX-6 Ninja.
That's unfortunate for you in the U.S., because the ZX-4 is a superb motorcycle. Its engine contributes strongly to its good performance, in both its lightness and its excellent power output. The 400cc ZX-4 engine weighs only 106 pounds, 40 pounds less than the previous 400cc Ninja engine. It's also inches more compact than the older engine. A downdraft-style cylinder head, much like that of the ZX-10 Ninja, works with a very oversquare (57 x 39mm) bore-and-stroke ratio to produce 58 horsepower, enough to propel this 335pound motorcycle to 12second quarter-mile times.
The engine revs without hesitation, and if you're not careful, it’s easy to pass the 13,500rpm redline and discover the ignition cutout at 14,500 rpm. It comes on the cam and pulls strongest above 9000 rpm. but even below that speed you don’t find there’s insufficient torque, probably because the motorcycle itself is so light and easy to accelerate. At our Fuji Speedway test session, the ZX-4 easily pulled to redline in topgear.just over 1 33 mph.
Rain dampened our test session, so it's not possible to make a final statement about the ZX-4’s handling. But, as far as we could tell, the aluminum twin-beam frame more than matches the engine's performance. In any case, the lightweight ZX-4 is very nimble and precise, with very strong braking allowed by its radial tires.
But, cheer up: While an enlarged ZX-4 won't make its way to America, perhaps Kawasaki will take the lessons learned from this machine and apply them to the next 600 Ninja. Koichi Hiro.
