Quick Ride

KAWASAKI ZEPHYR X

QUICK RIDE

Winds of change

KAWASAKI’S ZEPHYRS ARE named after a soft, warm breeze from the west. With the introduction of the new Zephyr X, that breeze has begun to blow a bit hotter.

At first glance, this secondgeneration Zephyr 400 looks identical to its predecessor. Its gray-painted wheels, black-painted engine and rear-end styling are a little different, but only a Zephyr owner would notice.

The main differences are inside. Satisfied with the Zephyr’s overall layout, but frustrated by its declining performance in comparison to the competition, Kawasaki engineers concentrated on improving its engine.

(The suffix X, pronounced kai in Japanese, is taken from the expression kai ryou ban, which means “improved version.”) The result is the company’s firstever air-cooled, dohc, four-

valve-per-cylinder head.

The engine remains air-cooled not only because Zephyrs have always been so, but also because Kawasaki recently released a liquid-cooled ZRX400 styled to resemble the 1982-83 Eddie Lawson Replica. Such is the popularity of standards, or “Naked Bikes,” in Japan that the manufacturer has two such 400s in its domestic lineup.

Kawasaki has consistently shied away from air-cooled four-valve heads due to cooling worries, but because the 400 shares the Zephyr 550’s cylinder block, engineers determined that there is sufficient metal between its smaller cylinders to provide the necessary thermal cooling. Just to be safe, they added a guide plate that routes cooling air over the center of the head, plus oil jets that spray the undersides of the pistons. The new, smaller valves use one spring each instead of the old bike’s nesting pairs, reducing friction, while a pent-roof combustion chamber replaces the old dome-shaped one, upping compression.

Chassis changes consist of twin Tokico front disc brake calipers sourced from the GPzl 100, sportier Dunlop Arrowmax tires and revised compression damping in the front and rear suspensions.

The Zephyr X clearly isn’t a racebike, but it acquitted itself quite well during Kawasaki’s press introduction at Japan’s Aida race circuit. It accelerates much quicker than the old bike, and is nearly 20 mph faster. Most surprising, however, is the fact that the increased power can be felt not only as the tachometer needle sweeps toward the 12,500rpm redline, but also lower down in the midrange.

Thanks to a new throttleposition sensor that varies ignition timing to coincide with throttle setting and engine rpm, response is excellent from as low as 4000 rpm-though you have to snick the slick-shifting transmission down at least two gears to achieve any sort of passing power.

The Zephyr X is more than a simple, inexpensive motorcycle-it is a fun machine that combines traditional styling with modern road manners. Hopefully, riders outside of Japan will someday get to experience a 550cc version.

Ben Matsui