Much work had been done to give the engine a clean, purposeful look. The CBX mimics the RCB with sharply angled cam towers jutting over a squared off cylinder head. Inside, four hollow inlet and exhaust cams connect inboard with Oldham couplers, adding two chains to spin the cams and the primary jackshaft with a heavier HyVo-type. Mixing moderately aggressive cam timing and the increased fuel/air volume of the 4v per-cylinder 'Pentroof' design allowed low speed tractability and spirited performance through the upper rev ranges. The over-square bore and stroke dimensions of 64.5 x 53.4mm encourage this quick engine spooling, capped by 9.3:1 pistons fed by a bank of six 28mm Keihin pumpers. Compare Honda’s (crank) rating of 103-hp against Cycle’s rear-wheel dyno figure of 85-hp to learn where the seeds of discontent were born, and even through lightweight magnesium was used throughout, the factory’s strict diet resulted in a still hefty figure of 555-lb dry. Nevertheless, Honda’s new CBX delivered on its promise, recording for the editors a fastest-ever time of 11.55 seconds and nudging a mathematical top-end of nearly 140-mph..


Honda CBX1000 (1978/9)
Engine: Air-cooled, 1047cc, 24v DOHC inline six
Bore x Stroke 64.5 x 53.4mm
Compression: 9.3:1
Fuel: 6-Keihin VB28mm
Ignition: Transistor
Transmission/primary/final drive:
Five-speed/HyVo chain/#530 chain
103-HP @ 9000 rpm
Chassis: Steel truss, engine as stressed member
Suspensions: 35mm tele fork, dual shock swingarm
Brakes: (F) 2-276mm (R) 1-296mm disc w/1p calipers
Wheels: Comstar composite
3.50V19 (F) 4.25H18 (R)
Dry weight: 549-lb
Top speed: 130-mph

Modern perspective:
Despite some favorability shown for the later sport touring models, enthusiasts overwhelmingly embrace the CBX as originally released; a dominate flyer flaunting the most visually impressive engine ever bolted to a motorcycle frame. This was the impact Honda wanted, and that initial success as a superbike contender has carried over to the collector. Owner support today counts mainly on a specialty aftermarket, and if so inclined my money would be spent on the second edition 1980 with its superior chassis but fit with the original Super Sport camshafts. The reality that shows the CBX as comparably inferior to the Suzuki GS now pales with the number of riders interested in testing the limits of either, but it is a rivalry worth noting. For as Suzuki followed the Euro practice of engineering harmony, Honda’s continental approach resulted in making the CBX among the most recognized, admired and desirable motorcycles in history. Nolan Woodbury
.

1981/2 1047cc, DOHC 24v six. Steel trellis frame, Pro-Link. 134-mph $5,595
Adding size and weight with a full fairing, saddlebags and even a safety bar, Honda’s decision to slot the six somewhere between the sporting 500 Turbo and touring GoldWing signaled its days as a flagship superbike were over. On top everything was new; tank, seat and remaining body panels all smoothly blending with the all black engine to make the CBX a slick, upscale traveler. A different design than the dirt version, the single shock Pro-Link rear suspension/swingarm allowed the luggage to tuck in tightly, while the front fork was uprated to 39mm tubes and set in new trees spaced 10mm wider. Rake increased to 29.5-degrees, stretching the wheelbase to over 60-inches, and the 81’s 295mm ventilated front rotors (identical to those used on the 1982 CB1100R) now used 2-piston calipers. Full of fuel, the CBX had grown to nearly 700-lb.

1975:  (< Mitch Boehm photo)
Still popular and for good reason, there’s no lack of good reading on the sixes’ development. A quick review takes us back again to the mid-1970s where founder Soichiro Honda and division president Tadashi Kume had recognized the need for a new sportbike. The CBX focus becomes sharper after learning designer Shoichiro Irimajiri was the man behind Honda’s championship six-cylinder GP racers. Now leading R&D, Irimajiri’s directive was to loosely base two new sporting flagships from the firm’s highly successful DOHC RCB works racers; a 1000cc four and Irimajiri ‘s six.

Perspective: Honda CBX 1000

Remembered as the greatest year of a truly profound decade, 1978 was classic theatre. Point to Honda’s CB750 Four of 1969 as the starting point for this script, and following the timeless SOHC the performers were established one by one. The proper chronological order of Yamaha, Kawasaki, then finally Suzuki entering the sweepstakes for big bore, four-stroke supremacy set the scene, and 1972’s 903cc Z1 delivered the first shot across Honda’s bow. The Zed returned Kawasaki considerable fanfare as did Suzuki’s GS four, but it was Yamaha that kicked the proverbial doors open in 1978. The all new, open class XS-Eleven shaftie truly shocked and rocked a reeling audience, until the spotlight shifted to Suzuki’s canyon carving GS1000. The best is the least known. Not to be outdone, Kawasaki finished the year-long barrage by mixing aftermarket pressure to boost the Z1R Turbo back into the performance headlines, but the explosive KZ/TC wasn’t the brightest star of 1978. That distinction belongs solely to Honda’s six-cylinder CBX 1000 Super Sport.

1980 1047cc, DOHC 24v six. 5-speed, steel trellis frame, twin shocks. 133-mph $4,195
In Honda speak, the term “refined” often means detuned, and that’s especially true during this era of ever-tightening regulation. All of this applies to the second-edition of the CBX, which according to published reports produced 16% less overall power. Don’t assume it’s all due to emission compliance, (which was a huge factor) but also pressure from safety cat politicians also played a roll. As mentioned, a growing number believed the open class motorcycle had become too powerful for its own good, and the result of this is why Germany imposed a 100-hp crankshaft limit. Still, buyers of the year two CBX could take solace in knowing the chassis updates applied to the new six made it a better motorcycle.

1978/9 1047cc, DOHC 24v six. 5-speed, steel trellis frame, twin shocks. 135-mph $3,998

Cycle magazine’s test published in February of 1978 stirred the pot for US enthusiasts, splashing the new six boldly across the cover months before other publications in a display of editorial clout. Billed as a 1979, some US contacts recall the CBX as a late-78 arrival, others didn’t see the big six until the next spring. In photographs or in person the engine dominates; continually taking your eyes away from the sculpted tank and Bol d’Or tail wing. Hanging the engine under, a mild steel tubular truss eliminates down tubes that would otherwise spoil the sight of six gleaming headers. Connected to each end, a conventional twin shock swingarm pivoted on plastic bushings and the 35mm fork was fixed at 27.5-degrees. Measuring 19/18” front and rear, Honda’s Comstar wheels used the same twin 276mm front units and 295mm rear (each with a 1p caliper) as the new 750F. Euro specification featured lower bars, rear-sets, and adjustable shocks. Color choices for 1978/9 mated silver or red with a wide black stripe and matt black side covers.

Seeking an impact to restore its performance image, the decision to make a statement with the (less powerful) but ever so sexy 24v six is a rare example where less equaled more. Many editors felt the CBX took motorcycling in the wrong direction with the unnecessary complexity of excessive engineering, but even the most jaded were seemingly seduced by the big Honda’s rip and symmetrical perfection. The 1000cc four project was developed into the CB900F Super Sport.

The effort made to improve the second-series chassis is noteworthy. The truss frame gained more rigidity and the steering head was lengthened by 2mm. While fork tube diameter remained 35mm, the sliders were larger and an air-assist upgrade followed external improvements to reduce stiction. Those cheezy nylon bushings fit to the original gave way to a mixture of needle and thrust bearings, and a 2mm larger swingarm pin. As with the rest of the 1980 line that used the Comstar wheels, the spokes were reversed, and the whole assembly was painted black with polished edges.

Searching for less noise and more midrange grunt in the machine’s new roll Honda addressed the engine again, altering the cam timing, carbs, airbox and exhaust. Adding durability, the cylinder head, valve seats and clutch were also refined and few complained, praising the CBX for its seamless power and improved over-the-road composure. Cycle’s ¼-mile times for the full-zoot 1981 model were actually faster than those run by the flawed 1980 test bike, but Honda’s plan to save the series (plus considerable development costs) by re-slotting it as Japan’s version of the Laverda RGS didn’t catch on. Most sat on the showroom floor until being heavily discounted, and that included the virtually identical 1982 version, finished in pure white with blue accents.

Inspiration for this review came from a recent project I did for RealClassic magazine on the Honda CB1100R. A great deal of time had passed since I’d looked into this most popular of all brands, and studying the line from inception to 80s endurance racing glory proved a timely reminder of Honda’s considerable reach. Count me as guilty in forgetting that no matter how large Honda’s automated machine had become, the passion that existed behind the scenes came from real, live motorcycle enthusiasts. An important part of its history, those frenzied six-cylinder GP bikes and world championships were understandably a point of pride, but in a classic case of success becoming indulgence, Honda’s decision to focus on production –but not leading edge sport bikes- resulted in a perceived detachment from a buying base demanding otherwise. 1975’s GL1000 opposed four did little to satisfy Honda’s sports buyers, and even a mountain of aftermarket speed goodies couldn’t keep the old single cam 750 on the forefront. .

The rear rim was wider and the oil cooler taller, but most everyone hated that silly, fed-mandated 85-mph speedo. It mattered little, for covered in a shade of deep black the CBX looks smashing. The tail featured a locked compartment for an anti-theft chain. For $180 a Euro control kit was available that included shorter bars, levers, switches, cables and brake lines.

Honda’s first step was to reduce camshaft lobe lift by .5mm and decrease the overlap for less unburned hydrocarbons. More changes included leaner carb jetting and deleting the primary (but retaining the secondary) main jet. Oddly, the exhaust featured reduced back pressure and a new performance ignition advance. An automatic vacuum petcock was added after some early versions flooded the cylinder with gasoline when parked on the sidestand with the fuel tap on. A common problem with the first-issue CBX was bent connecting rods when owners attempted to start the hydro-locked engine. Otherwise it was identical, still no wider than the Yamaha XS-Eleven four and receiving praise for its improved midrange and durability. In its April 1981 test of the new CBX sport tourer, Cycle charted the engine changes and touched on its disappointing 1980 test bike. “We reported the refined 1980 version was vastly slower, but it wasn’t. At least, not after the faulty ignition had been corrected. Still, the CBX continued to sell like cold cakes.”.

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