Honda Cr250r
HONDA CR250R
CYCLE WORLD TEST:
ONCE AGAIN NEW AND IMPROVED; BUT IS IT ONCE AGAIN THE BEST?
For the past couple of years, you could pretty much predict that two things would happen in 250-class motocross: Honda’s CR250R would be the best bike in the class; and Honda’s CR250R would be entirely different from the previous year’s model.
Things haven’t changed much this year. The ’84 CR250R seems to be living up to its reputation as the king of the 250 class, and the bike is completely new, as well.
Actually, as you can see, the new CR doesn’t look that much different from the previous model, but the truth is that virtually nothing will interchange between the two. Most of that is due to the fact that although the basic design of the ’84 CR is very similar to that of the ’83, their engines are mirror images of one another, that is, everything that was on the left side of last year’s motor is now on the right side, and vice versa. And when you add in all of the other changes that were necessary to allow that side-swap the pipe, the frame, etc. along with a number of overall improvements that include a front disc brake, the result is a different motorcycle altogether.
RON HUSSEY
According to Honda, the engine was flip-flopped so the kick starter could be moved from the left side to the right for easier starting, and to do away with the previous rear hub design that placed the sprocket and the rear brake both on the right side. By moving the chain and its sprockets to the left, Honda’s designers were able to tuck the rear brake pedal and its linkage in behind the frame’s rear downtube, thereby protecting them from grounding in ruts and during hard landings as on the ’83 model. Honda also claims that the change allowed the rear hub to be lighter.
But the really important differences are in the engine, and most are unrelated to the side-to-side reversal. The most significant is the addition of ATAC (Automatic Torque Amplification Chamber). The system is fairly simple in principle, consisting mainly of a small chamber cast into the cylinder housing, and a butterfly valve in the exhaust-port outlet. At low revs, the butterfly is open, allowing exhaust gases to flow into the ATAC chamber and increase the overall volume of the header pipe, which improves the engine’s bottom-end performance. As the rpm increases, a ball-ramp device driven by the right end of the crankshaft causes the butterfly to close, blocking off the passage between the header pipe and the ATAC chamber. That reduces the header-pipe volume, which boosts the high-rpm power output. And, since ATAC improves low-end power, the pipe itself could be designed for high-rpm operation.
In practice, the system seems to work nicely. The CR has a wide powerband and pulls strongly from low revs, but still has good top-end punch. There is some question about the reliability of the ATAC mechanism, which involves a complex linkage that connects the rightside ball-ramp mechanism with the butterfly-valve arm, which is on the left. Honda claims that any freeplay in the linkage, which has nine pivot points, is not as critical as with the linkage in Yamaha’s Power Valve System, and that all the pieces hold up well despite their lack of adjustability.
Not all of the new CR’s performance increase is caused by the ATAC system, though, because there is slightly different porting for ’84. Most of the ports, like the pipe, have been tuned for high-rpm power, and the exhaust port no longer is bridged. The reed block is the same, and its cavity in the intake opening has a plastic insert that directs the incoming mixture past the rough castings and corners. The head has a higher compression ratio, 8.6:1 compared with 8.4:1 last year, and it also has two water outlets instead of one to increase the flow of coolant. Overall, Honda claims that all these engine changes net a 3 bhp boost (43 bhp claimed) at 8000 rpm.
That’s not all the new stuff in the engine. The CR’s transmission and clutch are stronger for ’84, and the clutch-activating arm has been moved inside the primary case. The internal gear ratios are unchanged, but second gear—which proved very breakable for some racers last year—is 1.5mm wider this year. The clutch is basically the same but the plates are slightly thicker for better heat dissipation, and the clutch springs are stronger. And if you thought that the crank was the same, it’s not. Like the CR500 and CR125, the CR250 uses a full-circle crankshaft with a hollowed-out center that is covered with a steel plate. Thus, the crank is lighter than last year’s but its weight is concentrated at the outer edges where it provides about the same amount of flywheel effect. All of these new parts are surrounded by new cases.
Naturally, there’s a new frame to carry the new engine. The frame provides a slightly steeper steering rake, but new triple-clamps actually increase the trail by 2mm. The top triple-clamp incorporates rubber-mounted handlebar pedestals, and the steering head has been lowered 5mm and moved rearward 5mm to increase front tire loading in slippery corners. The rest of the frame is basically the same as in ’83, but with new pipemounting tabs and different radiatormounting points. The rear subframe is common to the ’84 CR125, CR250 and CR500. Undoing just four bolts allows easy removal of the subframe, with the airbox, silencer, seat and rear fender attached. It’s a handy setup for working on the shock at the track.
That shock is built by Showa, and it attaches to an aluminum swing arm that is 9mm narrower and a bit lighter this year. The shock also has a new linkage, including mildly redesigned forged-aluminum rockers and a longer frame-torocker strut, both to decrease the rearwheel progression rate. That change required altering the shock’s damping rates, as well. And since the hose running between the shock and the remote reservoir on last year’s CRs would often blow off, this year’s hose is larger in diameter, is a two-ply unit instead of one, and is clamped more tightly to the banjo fittings. The shock itself is 22.5mm longer and has a longer piston shaft, and a knob atop the reservoir selects any one of 16 compression-damping settings. Rebound damping is 16-way adjustable by using a flat-blade screwdriver to turn a small screw on the bottom of the shock. The change in rear-wheel progression also allowed the use of a spring that’s about one-third softer and substantially lighter in overall weight. The spring’s preloadadjuster ring now is on the bottom of the shock where it’s fairly easy to reach. We preferred the preload set so it allowed about 4 in. of rear-wheel compression with the rider aboard. Stiffer and lighter springs are available as options.
The ’84 CR’s Showa fork has 43mm stanchions, 12 in. of travel and less midrange rebound damping than in ’83. The fork is adjustable for air pressure, and it features a compression-damping blowoff valve in each leg that is adjustable to any one of 14 positions by turning a detented screw in the bottom end of each slider. Additional fork adjustments can be made by changing the oil volume or by purchasing the optional heavier/ lighter fork springs.
Brakes on the CR are top-of-the-heap, with a hydraulic disc up front, a singleleading-shoe drum at the rear. The front hub and disc are the same design as used on Honda’s XRs except that the disc is 0.5mm thinner for reduced weight, the master cylinder is smaller, and the frontbrake lever has a screw-type freeplay adjuster instead of a two-position camtype. The rear hub is new, and both hubs are laced with straight-pull spokes.
Elsewhere on the chassis, the aluminum dual radiators are mounted lower than before, and their air scoops are bolted to the tank instead of to the frame. The gas tank itself is slightly larger and mounted lower on the bike, and it, like the side number plates and other body parts, is made of plastic that keeps its gloss longer. The seat is redesigned once again, and like before, has an excellent cover and foam. There’s an optional seat that’s thicker to suit taller riders or those who just like a higher riding position.
You’ll probably enjoy riding the CR250R in any case, though, since it’s fast, efficient and is a genuine blast to ride. The bike starts easily, warms quickly, and runs cleanly. The ATAC system has added a lot of power at low revs and in the mid-range, although the Honda still doesn’t pull as strongly as an ’84 YZ250 at extremely low revs. The CR pulls well from idle, but it isn’t spectacular until it hits hard at around 4000 rpm—so hard, in fact, that it takes a few laps to get used to the abrupt surge of power. After a short while, most riders learn to momentarily fan the clutch lever when slamming into berms, which instantly puts the engine into the heavy part of the powerband and delivers a big burst of acceleration. But while the bike rockets out of the corners with this riding > technique, slippery, off-camber turns aren’t handled as well, because the CR can be a handful when it hits the power. Plan on the new YZ250s pulling you by a couple of bike lengths out of slippery turns, since they hook up better because of their smooth low-speed power characteristics.
A CR250 is going to out-stop the YZs, though, for the Honda’s brakes are the best you can get. The YZ250 has good brakes, too, but the difference is noticeable late in races that last for 30 or 40 min. The CR’s disc never fades and the required lever pressure stays constant.
The CR250R is quick-handling through tight turns, which makes it possible, once you’re accustomed to the quickness, to take the inside line under most other brands of motocrossers. The CR will do a noticeable headshake going into whooped turns, though, when the brakes are applied hard and the shock preload is incorrectly adjusted. If the preload is too stiff, the front end will shake violently. If the rear end is adjusted to 4 in. of sack, the shake will hardly be noticed. The suspension is well-balanced and delivers a comfortable ride, and its action stays consistent throughout long motos on rough tracks; only the hardest-riding pros should notice any shock fade at all. So are the standard fork and shock springs spot-on for all but the top-level pros. The shifting is smooth and positive for everyone, though, just as the internal and external gear ratios are near-perfect; and the bars, levers, throttle, seat, footpegs and control cables are flawless.
That’s why the ’84 CR250R picks right up where its predecessors left off: ahead of the competition. The CR250R has been the hottest 250 motocrosser for the last couple of years, and the others* haven’t caught it yet. If Honda keeps changing the CR every year, maybe they never will. El
HONDA
CR250R
$2418
