Honda CBX

Honda had produced a Honda RC series six-cylinder race bike in the mid-1960s, but the CBX was Honda's first production 6 cylinder road bike with this GP racing engine technology.[9] The CBX's advanced DOHC 24-valve inline six-cylinder engine was its outstanding feature; but in other respects the bike was conventional, having telescopic forks, a tubular frame, twin rear shocks and straight handlebars.[6][8]

Although bulky, it was only two inches wider than a CB750,[9] the engine was wide only at the top. The width across the crankshaft was relatively narrow as the CBX had a stacked engine accessory arrangement, whereby the alternator and ignition items were positioned behind the cylinder block. This arrangement produced an acceptable engine width low down and moved critical items out of harm's way in the event of grounding.[8]

Journalist L. J. K. Setright wrote of the CBX's width: "Don't tell me that its engine is too wide: It is no wider than the legs of a rider, so it adds nothing to the frontal area, and personally I would rather have my legs shielded by a cylinder apiece than exposed to every blow ..."[10]

In the February 1978 issue of Cycle (magazine) editor Cook Neilson wrote this of a review of a pre-production bike, after a four-day review at Orange County Raceway, Willow Springs Raceway, and the Webco dynamometer: "The objective - to build the fastest production motorcycle for sale anywhere in the world - has been met." [11] Comparing the CBX to the CB900F, Setright added,"The CBX feels better and goes better, and the difference is greater than the difference in price, so the costlier bike is actually the better bargain. ... The CBX engine is as responsive as a racer, the nicest cycle motor to ever reach the street.".[10]

The CBX was not the first production motorcycle to be powered by a six-cylinder engine (the first was the 1972–1978 Benelli 750 Sei, based on the Honda CB500 Four) but it was the latest and most advanced entry into the competitive superbike market. A review in Cycle magazine called the CBX a "breakthrough for the Japanese motorcycle industry" and praised its design, concept, and performance.[12] The CBX was available on the market in late 1978, and the production model was even faster than the prototype.[8] Cycle World got a tested 1/4 mile time of 11.64 seconds at 117.95 mph (189.82 km/h), the 1978 bike was also the first bike they tested to go over 130 mph (210 km/h).[1] The 1979 CBX could cover a quarter mile in 11.36 seconds with a terminal speed of 189.82 km/h (117.95 mph).[13] But later CBXs with the addition of saddlebags and a fairing were detuned, and showed the 1981 CBX had lost five hp compared to the 1978 model, from 105 hp down to 100 hp.[7][6]

Cycle Guide praised the bike as "the Vincent Black Shadow of 1979" upon its introduction.[14] In 2011, Australian publication 2 Wheels Magazine named the CBX as one of their favourite 12 superbikes ever.

To avoid confusion with Honda CBX series bikes, the CBX is sometimes referred to as the CBX1000.

In 1984, the Frenchman Georges Martin of the French firm Moto Martin, designed and built a lighter and stiffer nickel tube frame capable of controlling the CBX motor, and supplied this chassis in kit form.

The original bike had handling issues if ridden hard and was heavy at 260 kg (580 lb). Moto Martin isolated the handling problems and eliminated them by unbolting the engine and throwing everything else away. The new frame was both stiffer and lighter than the original and tied the front and back of the bike together. The stock 37mm tubes were replaced for 42mm Moto Martin forks and mounted the single, rear shock horizontally under the seat. They used Brembo brakes and a one piece fiberglass seat/tank/tail section café racer style and managed to lose nearly 36 kg (80 lb).

A 1984 issue of Cycle News praise the Moto Martin’s road manners. Smith says his bike is “always stable.” Cycle News shaved four seconds off the previous best CBX lap time at Willow Springs.[15][16][17]

• Honda CBX
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  Sport touring model
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  custom
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  Moto Martin-framed CBX
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  Honda CBX Engine Detail
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• Kuch, Joachim: Honda. Motorräder seit 1970. (in German) Stuttgart: Motorbuch-Verlag, 2000, ISBN 3-613-02061-0, p.50-51
• Limpf, Martin: Das Motorrad. Seine technische und geschichtliche Entwicklung dargestellt anhand der einschlägigen Fachliteratur. (in German) München: R. Oldenbourg Verlag, 1983, ISBN 3-486-27571-2, p. 59-63
• Foster, Ian: The CBX Book, part 1 and 2

List of Honda engines