Kawasaki Kx250a
KAWASAKI KX250A
Cycle World Road Test
Many more improvements than just those that meet the eye.
■ THIS YEAR it wasn’t so easy. Public pressure dictated to the manufacturers that they had to do something to the rear suspension of the ‘75 bikes if they ever expected to sell them. Just about everyone has given in. Long-travel rear suspension is here to stay. There are several reasons for it. First and foremost: it works. Bikes handle better, deliver more power and are more comfortable to ride. Second, it’s what the pros use and that means every kid on the block wants the same thing. If Heikki Mikkola or Roger DeCoster won his next race wearing full leathers and an external goodie guard, Sunday at Saddle-back would be an endless parade of the very same thing.
The obvious change in the new KX250A, then, is the rear suspension. Not only is it LT, but it features gas/oil shocks. These items are new on the market as far as Kayaba, their manufacturer, is concerned. The shocks’ principle has been known to engineers for many years, but only now has it been marketed. Kayaba is the Japanese manufacturer that makes most of the regular suspension components for Kawasaki, Yamaha and Suzuki. They do a little work for Honda, but not as much. The shocks are large, heavy items. But they work, and that is the key.
Maico forward-mounts its, Husky and Montesa use the lay-down method. Kawasaki utilized a little of both. The shocks, which are mounted in an inverted (upside down) position, are a little farther forward and slanted more than before. This combination provides nearly seven inches of travel at the rear axle. Spring rates are just right for about a 175-lb. rider. As the springs wear, you’ll be able to re-firm them through the five-position preloader on each shock. All in all, it is a vastly superior system.
At the other end is a pair of totally new forks. Although travel is up only 5mm (total travel is 195mm or 7.7 in.), the action of the forks is much improved. On our last KX250 (CW, June ‘74), the forks worked superbly over an occasional hard jump or bump, but they suffered from hydraulic lock when subjected to a series of stutter bumps or potholes. This has all been cured. The forks have totally new internals. Damping is very close to ideal, although lighter riders found that the forks did not work as well for them as they did for heavier riders.
The size of the fork legs is large at 36mm, but the top eight inches of each leg have been turned down so that small, light top clamps might be retained. Unless you intend to ride trials, there is no reason to change the steering. As it comes, the bike steers very quickly. At least the front does; the longish wheelbase keeps the whole bike from overreacting. The geometry is close to ideal for most tracks. But those that have very fast, deep whoopers may find that the KX cannot handle them as easily as it does everything else. The bike shakes its
head when asked to go fast over rough terrain. This is one of the drawbacks of quick geometry. We experienced the same sensation on our previous KX250. Usually a forward-mount modification will aggravate such a condition, since it raises the rear end of the motorcycle and reduces the rake slightly. But our bike was no worse than before. No better either.
With the geometry as it is, inside lines are a breeze with the KX. So are quick bermshots; but you’ll rarely find using the berm in its entirety to be the fastest way through a corner. Front-end traction is not adequate. The bike can cut a much tighter line than the Dunlop Sports tire will let it. The 4.60-18 rear tire is fine for most everything, but get a Metzeler for the front.
The chassis is identical to last year’s, with the exception of the modification for the new shock position. Single-downtube split-cradle frames are usually the norm when dealing with an engine that has an offset exhaust port. The frame is made from Japanese chrome moly, as is the swinging arm. Frame strength is good, but we did detect an occasional flex of the swinging arm through deep, high-speed whoopers. It’s a shame that, since the swinging arm is already gusseted, Kawasaki didn’t see fit to use just a slightly larger, and therefore stronger, gusset to alleviate the flex in the arm.
In the engine compartment, things remain nearly untouched. The transmission is identical to the first one. Carburetion is still via a 34mm Mikuni that comes with one of those confounded pull-up choke mechanisms. You can purchase from Sudco Inc. a lever attachment that makes choke operation much less of a hassle.
KAWASAKI KX250A
$1216
PARTS PRICING
Cylinder porting is unchanged. The bike was fast last year and it remains so for ‘75. The power is strong from 4500 rpin on up. Spacing of the gear ratios is not as close as you might expect, and the KX can pull a slightly larger spread of ratios than other pipier 250s. The engine’s bore has been enlarged from 69.5 to 70.0mm; this brings the total displacement up from 246cc to 249cc.
There is a strange similarity between this transmission and the Yamaha YZ trans. The Yamaha has a much shorter throw, but the sensation of gear selection is almost nil with each. Even when shifting without the clutch, the KX feels as though the lever is not connected to anything, like it’s just slicing through an empty space. But gear selection was, for the most part, positive. A few times the bike jumped out of second gear, but never when we made sure that it was properly engaged. The shift lever is very similar to the Yamaha’s. It is short and knurled at the tip. But it will not inflict the same type of through-the-boot blisters that the YZ’s will. Although you may not feel the next gear engage, you can at least feel the Kawasaki’s lever move; therefore, you more quickly release pressure on the lever and on your toe.
For braking on the KX, Kawasaki has eliminated its full-width front hub and gone to a KX125-type conical unit. Not only is it lighter, but the smaller hub has proven stronger, as well. The rear binder is still half-width on a very wide hub. The heavy triangulation that such a hub provides ensures wheel strength. So do the D.I.D. rims that are standard.
The handlebars that we didn’t care for last year remain. The awkward position in which they place your hands, wrists and arms, aids premature arm fatigue. At your first chance, replace them with an aftermarket bar with a bend that you prefer. Our favorite is a CZ-type bar.
Seat foam is denser now than before. No longer do you hit rock bottom as you ride. The saddle is ample and comfortable.
Firing up the KX is no problem. The machine will sometimes kick back, but not savagely. Once the engine lights up you can almost immediately release the choke. The first thing you’ll notice, particularly if you fire it up before you put your helmet on, is the incredibly loud exhaust. The exhaust pipe sports only a token silencer. The bite is taken out of the bark, but the bark is still plenty fierce. Starts are best accomplished in second gear. First might be ideal for really tacky areas, but first gear is so short, and shortshifting second so essential, that you find yourself having to execute a gear change about the same time that your rear wheel is passing over the fallen starting gate. Instant dead last. It is best to use second. For dry starts, sit forward, wing it and let the clutch go. Where traction abounds, judicious clutch slipping will get you moving. Once you get over that starting gate, let ‘er rip.
We said shortshifting second gear works best because the strong torque curve provides hard acceleration. Shortshifting first through fourth is wise, but as you go up through the gears, wind each one a little higher than the previous one. Never shortshift fifth.
The engine is a strong puller, but it is still just a 250. One advantage of the torque curve shows up when exiting corners. Usually, you have a choice of two gears that will work. One is obviously a little better than the other, but this extra gear makes for a forgiving ride, especially for novice racers who sometimes lose track of how many downshifts it takes to set up for the next bend. :
Engine response is zippy—as with last year’s motor—at least when you’re standing there blipping the throttle. On the track it’s a different tale. The long-travel suspension soaks up more bumps and keeps the rear wheel in more constant contact with the ground. Whereas the first KX250 might zip about in tractionless bursts of wheelspin, the greater traction provided by the new shock position transforms those wasteful bursts into forward thrust.
A few more items did receive needed attention. Footpegs come spring-loaded and they are more in the Elsinore mode than the old KX style. We should mention that these footpegs also come on the KX125. The grips are good, buf not great. Levers are plain old alloy stuff, but they do have grit covers. Normally such paraphernalia does not impress California riders, but this winter has been particularly wet. Now we appreciate them more. The fenders are the same as last year: white plastic items, but they didn’t crack this time around. We crashed a lot less on this better-handling KX than we did on the old one though. No doubt this was a contributing factor to the fenders' survival.
The new KX250A has about the same amount of power as before, but it gets it to the ground better. Despite the rest of the machine’s improvements, this is the most important. It takes a bike that was competitive last year and makes it competitive this year. Mean green lives on! B§1
