Our first contact was with Jon Seidel, a longtime American Honda press manager. Seidel was under the impression that there was no significant meaning behind the letters, but he passed the question along to Gary Christopher, a senior manager inside American Honda.
Christopher then proceeded to reach out to several individuals inside the company to see if anything could be discovered regarding the CB classification. Here’s what he found.
Like Seidel, Christopher had been told by a number of Japanese staff over the years that CB was no more than a model designation, with no particular significance attached to it. He contacted Bob Young, a longtime National Service Manager at American Honda, who was also heavily involved with the development and testing of the CB750, and “Mike” Hishiki, a longtime test rider and development team member of Honda R&D for their take.
Young and Hishiki also had never heard any specific words attributed to CB, thinking it was just the next logical step from the C-series (C100 Super Cub for example), to the CA-series (like the CA71) to the CB. The two could not remember any time when Mr. O. Saito, a project lead engineer on the CB750, referenced any meaning, such as “city bike,” to the CB, nor was there any confirmation that Mr. Honda ever uttered “chokusetsu baiku” in reference to the letters.
Christopher’s conclusion is that, though later models may have been assigned specific meanings in accord with the model designations, the CB was just the next step in a series of model identifiers of the time. It’s not an earth-shatteringly sexy revelation, but that’s probably as solid an answer as we’re ever going to get.