Honda model ("RC") numbers explained...

...even if you didn't care.

From VSource.org:

Honda Model Numbering System

Honda Model Numbers appear in the VINs of all Honda models using the VIN system (to date, this now includes most countries, except France...) (There is more about the construction and use of VINs on this page.) Model Numbers also tend to define the various "generations" of related Honda motorcycle models, though this is not always the case. The 1990-97 VFR750FL-V models share the same Model Number (RC36), but are generally divided into two "generations" (FL-P and FR-V), while the earlier generation 1986-89 VFR750FG-K has a different Model Number (RC24). What causes Honda to assign a new Model Number probably relates to significant changes in engine design, but this has not been confirmed by Honda.

Unlike Honda Parts Classification Numbers, Honda Model Numbers are relatively simple to understand. As can be seen from viewing a list of Honda models and Model Numbers arranged according to engine capacity, since approximately 1979 Honda motorcycles have had Model Numbers beginning with A (50cc to 79cc), H (80cc to 124cc), J (125cc to 149cc), K (150cc to 184cc), L (185cc to 199cc), M (200cc to 349cc), N (350cc to 449cc), P (450cc to 649cc), R (650cc to 899cc) and S (for 900cc and up).

The second position in the Honda motorcycle Model Number is occupied by a letter relating to the type of motorcycle. For example: "C" is a street motorcycle, "D" appears to be a dual-sport, "E" is an enduro (or perhaps an off-road model) and "F" is a scooter.

The numerals in the Model Number do not seem to be particularly significant, with the first model in each category named "01" and the next to be developed taking the next available number. However, it seems likely (or extraordinarily coincidental) that the NC30 was intentionally named after the RC30, but then it is somewhat baffling why the RVF400R, the "baby RC45", was named "NC35" rather than "NC45".

Apparently, this system was too complicated for American Honda to deal with, when they decided to call the VTR1000 SP-1 (SC45) the "RC51" in the United States for what could only be blatant marketing reasons... To be fair to American Honda, model names are often tailored to the local market where the particular model is intended to be sold—and these model names can be different in different markets. A perfect example is the VTR1000F, which is knows as the "Super Hawk" in the United States and the "Firestorm" in the UK (and perhaps in other markets as well). Another example of market-specific nomenclature is the early RC36, which was known as the "Carat" in France. However, in VSource.org's humble opinion, to use a model name that imitates a Model Number that could not possibly have applied to the motorcycle in question (the "RC51" has an engine size larger than 899cc) is a bit misleading, if not cynical.

In addition to the names and designations given to particular models by Honda and its distributors, popular motorcycle models sometimes become better known by their nicknames or their Model Numbers than their "official" names. The VFR400R is probably better known as the "NC30", for example, and the three CBR400 variations are sometimes differentiated by the nicknames "Aero", "Tri-Arm" and "Gull-Arm". Similarly, the RC30 (VFR750R) became known better by its Model Number than by its Model Name, and in some markets the Model Number was used in marketing materials and even found its way onto the rear cowl. By the time the RVF750R (RC45) was released, Honda was fully exploiting the "heritage" aspect of Model Numbers for marketing purposes—no doubt much to the surprise of the Honda engineers who had developed the numbering system 15 years previously...