Kawasaki Kx125
RON HUSSEY
KAWASAKI KX125
CYCLE WORLD TEST
MORE THAN 90 PERCENT NEW.” IT SAYS, RIGHT ON Kawasaki’s brochure for the 1988 KX125.
But it doesn’t really say why the bike is more than 90 percent new, or why that’s a good
thing. These days, newness simply is expected in 125cc motocross bikes. Buyers have become accustomed to seeing 125s that are substantially changed, if not entirely different, every new model year.
For the most part, these frequent changes benefit the buyer by improving overall performance and eliminating the pitfalls associated with previous models. But new models also mean a new crop of pitfalls, including bikes that cost substantially more than the preceding ones. They also mean that the riders have to forget most of the suspension and engine-tuning tricks they just spent a year learning.
This certainly applies to the ’88 KX125: Just as Kawasaki claims, it is about 90 percent new. Only the basic wheel assemblies and a few engine parts are the same.
Most of the more-radical changes are in the engine. One involves the exhaust-control system, which, as in KX 125s of the last few years, uses little valves to open and close two auxiliary exhaust ports according to engine rpm; but the system now also has a larger valve that alters the height of the main exhaust port. In addition, a new, 35mm Keihin carburetor with a crescent-shaped slide feeds the engine through a six-petal, carbon-fiber reed that leads straight into the crankcase instead of through the barrel as on previous KX 125s.
Remaking some motocross magic
These changes contribute to some mighty impressive performance. The engine carburâtes cleanly at any throttle opening and responds w ith incredible quickness. Midrange and top-end performance are truly impressive, although there's not much low-rpm power. But for moreexperienced 125 riders, the lack of low-end matters little. The engine is fiercely competitive when in its powerband; and if the revs drop too low, a fan of the clutch lever quickly brings the rpm back up into the go-fast zone.
A new, close-ratio six-speed gearbox helps the rider keep the engine working in its optimum power range. And the clutch has an extra set of plates, as well as stiffer pressure-plate springs (five in place of the six previously used), the better to cope with any fanning that might be necessary. There also is a separate cover that can be easily removed for clutch inspection and maintenance without fooling with coolant hoses or the kickstart lever.
Kawasaki didn't forget the rest of the bike when re designing the KX125, particularly the suspension. Up front, a new KYB cartridge fork-which has 16 external compression-damping settings—works exceptionally smoothly and controllably at both racing and trail speeds. The rear suspension (which has a more-progressive linkage and a revalved shock with a 2mm-larger shaft) is equally adept at soaking up potholes, whoops, jump landings and all other racetrack treachery.
That marvelous suspension is just part of a well-balanced chassis that makes the KX125 a great handler. The '88 frame has a steeper head angle, a larger-diameter front downtube, a stronger aluminum swingarm and a shorter, stiffer rear axle. Altogether, these components make for a stable, solid platform that goes where it is pointed and lets the rider pick his lines through corners with little thought as to berms, bumps, grooves or off-cambers. You can go for the inside, the outside or the middle line; the KX doesn’t care.
Neither does it have any preference for soil types: It handles as competently in sand as it does on loam or hardpack. Straight-line stability at speed also is very good, second only in the 125 class to the 1988 YZ125.
But the Kawasaki is second to none in braking control, feel and power. A new master-cylinder leverage-ratio boosts the strength of the front disc by a claimed 15 percent. The rear disc brake also is excellent, operating with minimal effort and providing good rider feedback.
As you can see, the KX gave our testers little reason to complain. Almost every rider did moan about the hand levers being too close to the handlebar, however, and the extremely short kickstart lever (a common complaint about all modern 125s) was disliked by everyone. Thankfully, only one or two kicks are needed to bring the engine screaming to life. A few other gripes concerned the seat, which doesn’t allow the rider to move around very easily. And the seat’s too-soft foam gets pounded into lifelessness after just a few days of use, leaving the rider able to feel the seat base on practically every bump.
Okay, so Kawasaki didn’t build the perfect 125 motocross bike: neither has anyone else. But the KX125 is an excellent racer that shows a lot of attention to small details and trick stuff: The large airbox has an adjustable air-inlet shutter on both sides; the footpegs have aggressive tops and are extra-wide to spread the load across the rider’s instep; the wheels are strong and trouble-free; the rear brake pedal has a height adjuster and a folding tip; and all of the controls work smoothly with minimal effort.
Indeed, this Kawasaki 125 has a lot going for it. But how does it stack up against the rest of the '88 125s, you ask? Well, for Expert-level riders, the KX’s power and suspension put it right at the top of the heap. But for more-mortal riders, the Yamaha YZ125 (Cycle World March, 1988) has more low-end power and is much easier to ride. Suzuki’s RM 125 has knocked itself out of the running with reliability problems this year, and the Honda CR 125R is plagued with suspension woes.
So, despite its few flaws, Kawasaki's 90-percent-new 125 has done very well for itself. Who knows? It may even be good enough to leave alone for a year or two. Eä
KAWASAKI
KX125
$2399
