Oblivion has been the final resting place for many 1970s and early 1980s Japanese motorcycles, but not the Honda CBX.
The Honda CBX was always special, and although only released in 1978, by 1980 it’s cult status already saw the creation of an International CBX Owners Association. More than forty years on the CBX has become an allegorical embodiment of what Honda represents. As a technological innovator, Honda has often pursued an independent design path, and their quest for dominance on the race track led to the RC165 six-cylinder 250 in 1964. It was the six’s triumph that provided the Japanese company credibility in the occidental club dominated by Britain and Europe that then controlled motorcycling around the world.
But by the mid 1970s Honda’s motorcycle development was in the doldrums. The company had become preoccupied with car manufacture and Honda had lost their performance image. They needed a knockout motorcycle; the fastest motorcycle in the world, and one to make everyone gasp. Honda’s response was the six-cylinder CBX1000.
The CBX project leader was Shoichiro Irimajiri, designer of the famous racing sixes in the 1960s, and his influence saw the six-cylinder design prevail over a four-cylinder that was developed in parallel.
The 1,047 cc in-line six cylinder, with double overhead camshafts and four valves per cylinder owed its genesis to the racing versions, and took Irimajiri one and a half years to complete.
The forged crankshaft ran on plain bearings, with a Hy-Vo primary drive to a jackshaft behind the cylinders running the alternator and ignition. This helped minimise engine width, as did chamfered outer crank webs.
Although it looked wide, the engine was only 50 mm wider than the four-cylinder CB750. The CBX exhaust system was a six-into-two, and during its development Irimajiri taped the sound of F4 Phantom jet fighters with the intention of replicating it in the CBX exhaust system. Although they were successful the Phantom exhaust was vetoed as Honda didn’t want to build a motorcycle that sounded like a jet fighter.
The inlet manifolds for the six 28 mm Keihin CV carburettors angled to the centre to allow room for the rider’s knees, and the CBX produced 105 horsepower at 9,000 rpm, considerably more than another other production motorcycle in 1978.
The engine dominated the motorcycle to such an extent that the chassis was almost secondary to the design. This emphasis on the engine over the chassis was typical of Japanese motorcycles of the 1970s but the CBX took this philosophy to an extreme.
The imposing impressive engine hung from a braced steel frame, with a slender swingarm pivoting in plastic bushes. The front fork was a spindly 35mm, and the FVQ shock absorbers faded under hard use. It was no coincidence they earned the nickname “Fade Very Quickly.” The braking system was also marginal, with twin 276 mm front discs with floating single piston calipers, and a single 295 mm rear disc.
Irimajiri went to a considerable effort to reduce weight, incorporating magnesium engine covers, 19 and 18-inch Comstar wheels with aluminium spokes, and forged aluminium handlebars and footpegs. Despite these lightweight components the CBX’s dry weight was still a considerable 247 kg. And along with the weight came large, and somewhat intimidating, overall dimensions.
The CBX was a brute, not a svelte sporting bike. The styling also was one of Honda’s most successful, the open cradle frame allowing the motor to dominate. Each component was carefully chosen to ornament, and exalt, the six-cylinder masterpiece. The CBX was also cleverly scaled up in size to provide the impression of a smaller motorcycle. Typically Honda to ride, the controls were linear, predictable, crisp and precise.
Unfortunately the CBX landed smack in the middle of a Superbike war. It was fast enough, and powerful enough, but the power only emphasised its underlying weakness. Weight, width, and a frame and suspension that was barely adequate.
Some of these handling problems were addressed for 1980, but lower lift and shorter overlap camshafts saw the power reduced to 98 horsepower. Now slower but still heavy, the Superbike crowd continued to shun the CBX. Honda’s own, cheaper, CB900F was almost as fast, and handled better, so the CBX was refocused, into a sport tourer for 1981. By 1983 the CBX had no raison d’être and quietly disappeared.
It may not have lived up to its initial expectations but it was still the most stylish six-cylinder motorcycle ever. The CBX was also the embodiment of the most aggressive marketing policy in Honda’s history. Honda didn’t need to build a six, but their corporate persona required a six for emotional, rather than engineering reasons.
The CBX may have been a sales disaster for Honda, but it has become a monument to their capability. And as with many classic motorcycles it is now the first model that is the most coveted. Exuding elegance and class, the original CBX is one of those rare motorcycles that will never be forgotten.
Ian Falloon is the author of more than 45 books that cover a variety of brands and motorcycle models. He has recently updated his Ducati 750 GT to now describe a rare 1973 version that he had not seen before.
This new edition is available to order for AUD$120 (free worldwide shipping) payable to PayPal.me/ianfalloon. For all those who have already purchased this book, Ian is providing a high resolution PDF free of charge of the new edition.
Australia’s go-to-guy for classic motorcycle wisdom. Ian has written nearly 45 books on motorcycles that each offer unparalleled insight on the historical and technical development of particular makes and models.