|1981 Honda CBX Road Test - page 3|
Transmission ratios in the Honda's fivespeed box are unchanged from the 1980 CBX, as are primary and final drive ratios. Gear ratios are well spaced and riders can pick from a wide selection in the useable range of rpm depending on urgency, what with 57.4 mph available at redline in 1st gear. The engine purrs along at 4228 rpm at 60 mph in 5th gear. Final drive is via 530 O-ringed chain. Would touring riders mind a big roadburner without a shaft, we asked the Honda people. No, they said. Most people who think of themselves as sport riders still prefer chain drive; the touring popularity of the 750F has shown that.
Starting the CBX is easy, if you don't do much work. When the engine is cold the drill is to push the handlebar-mounted choke lever full on and punch the starter button without so much as touching the throttle. The engine is neither hot nor cold blooded; it likes a little warmup to really run with conviction, but can be nursed away on partial choke if you are in a hurry. Hot starting also works best with a light, or absent, touch on the throttle. As mentioned, the CBX can be a peaky devil on takeoff from stoplights, a trait not helped by slightly vague clutch engagement. After one or two lunge-and-bog movements in traffic, the rider learns to feed some revs into the clutch as he slips it, and then everything is fine. Really lively throttle and clutch work can produce easy, predictable wheelspin on demand.
When we first rode the CBX, a tankful of low-rent gas from our friendly Fly-By-Night station had the engine pinging badly at every launch. With better fuel, however, the problem went away and we had no such problem using unleaded premium or leaded regular. Worth noting, however, that the Six is sensitive to fuel quality. It also likes a fair amount of fuel; not hoggish by any standard, but a bit thirstier than the mere run-of-the-mill Four. On our legal-speed test loop the CBX got 41 mpg. But in a spirited search for hidden radar - which we found, by the way - mileage hovered just over the 30 mpg mark. The tank is big, with 4.6 gal. of ON and 0.7 gal. of RES. available, but hard riding makes the big tank a welcome feature on a long weekend loop.
Hard riding also builds appreciation for the chassis and suspension improvements wrought on the new CBX. The big change this year is the switch to Honda's Pro-Link monoshock rear suspension. The Pro-Link system uses a set of hinged levers beneath the heavy-duty aluminum swing arm to feed suspension movement into a single large spring and shock absorber unit which is situated in roughly vertical position just in front of the rear wheel. Changes in leverage during swing arm movement cause the arm to lose progressively larger amounts of mechanical advantage over the spring and shock as suspension is compressed toward full bump. The ratio between swing arm and spring varies from 2.78:1 at full extension down to 1.92:1 with the suspension bottomed out. This rising rate arrangement allows the suspension to move easily and compliantly over small road irregularities, but firm up as shock loads and riding conditions force the swing arm closer to the end of its travel.
To further enhance the progressive nature of the suspension the rear spring and shock unit uses compressed air to assist the coil spring. Air too provides a progressively stiffer resistance to movement as it is compressed, and the CBX relies heavily on the air charge in the shock for its rear suspension. An air valve just behind the right sidecover is used to fill the shock, and the owner's manual recommends 28 to 56 psi. If for some reason air pressure is lost, a warning light will flash on the instrument panel. If this light comes on, the rider is supposed to reduce speed to below 50 mph and proceed immediately to the nearest service station to add air. "Do not continue riding," the manual warns, "because stability and handling may be adversely affected."
The ride on our test bike felt best, for combined comfort and stability, with air pressure at the maximum level. As an added variable in the rear suspension package, the CBX has a three-position knob to adjust shock damping. The push-pull knob protrudes from the bike just beneath the right sidecover, or behind the rider's right ankle, and once you know where to reach without looking, can be adjusted as you ride. The softest setting felt good on bumpy freeway surfaces, though the bike wanted to wander and hunt a little more over rain grooves and pavement seams. For all other conditions - especially hard riding through the mountains - full damping felt best, giving the bike a noticeably tauter, more precise feel.
The front suspension, too, is air assisted, and fork diameter has been increased from 35 to 39mm, same as the GL1100. To accommodate the extra thickness, the fork legs are now an extra 10mm apart. Dual syntallic low-stiction fork bushings are used. Also changed is fork geometry. Using the Pro-Link suspension lengthened the wheelbase from 59 to 60.4 in., and the forks have been angled to give an increase in rake from 27.5° to 29.5°, while trail has remained at 4.7 in. Wheel widths on the ComStars have been bumped up front and rear. The front is now 2.5 in. wide rather than 2.15 in. and the rear is up to 2.75 in. from 2.5. The tires are Dunlop V-rated Gold Seals, suitable for speeds beyond 130 mph, a 3.25V-19 up front and a 130/90V-18 rear.
If all this sounds like a recipe for a long, slow steering bike, it is and it isn't. The CBX is long and feels it and the bike has a stability in sweeping, high-speed corners common to motorcycles with slow steering geometry The nice part, however comes in riding around town and pushing the bike through slower corners, because then you discover how little penalty there is for those good road manners on the open highway. For a big, heavy, wide and reasonably long motorcycle the CBX makes it over the slower hurdles in life with remarkable ease. On mountain roads it feels like a fullback with three years of ballet lessons under its belt. Steering is precise -- the bike goes where you point it -- and sudden changes of line in fast corners (as when an oncoming pickup truck loses the rear end halfway through the curve) are handled with grace and the pleasant absence of tank-slapping motion. In most of the sudden demands of fast daily riding, the bike is hard to upset. Even quick transitions through an S-bend demand relatively little effort -- more effort, certainly, than an RD400 would require, but not as much as you would expect from a 662 lb. superbike with a fairing and saddlebags.