The Honda CBR400RR is a Japanese domestic market small-capacity sport motorcycle introduced by Honda in 1988 as a further evolution of the popular CBR400R, which dated from 1986. The CBR400R and early CBR400RR models both carry the Model Number NC23, which makes up the first part of these bikes' Frame Numbers. The early NC23 was designated CBR400R and is also known as Aero, Hurricane or Jellymould, as it shares its major design features with the rest of the early CBR family of motorcycles, which included significantly rounded body shapes, whereas the later NC23 is designated CBR400RR and is also known as the Tri-arm, after its racing inspired braced swingarm.
However, the CBR400RR is considered the most closely related of Honda's 400cc models to the CBR900RR or Fireblade series of large-capacity sport motorcycles. The CBR400RR preceded the 900 cc (55 cu in) Fireblade by four model years, going through one major rework (signified by a new Gull-arm swing arm design and a new Model Number, NC29), and several years of production in its new form before acquiring the FireBlade name for the 1994 model year.
The CBR400RR models, therefore, consist of the later NC23 CBR400RR-J (1988) and CBR400RR-K (1989) models as well as the NC29 CBR400RR-L (1990 & 1991), -N (1992 & 1993) and -R (1994 onwards). The name Tri-Arm is shown on the CBR400RR-J's bodywork, along with Hurricane, but the CBR400RR-K dropped the latter designation.
The NC23 CBR400RR features a standard extruded beam frame, the rear of the seat unit slopes forwards, and the seat unit subframe is totally separate from the main chassis of the bike. The NC29 (only the -R models of which carry the FireBlade name) had several modifications to the frame. The main rails were of a 'cranked' design, the seat support structure had a larger rail that was welded to the frame, the rear of the tail section now had a slight recurve to it, and the swingarm was given a gull-wing shape on one side to give ground clearance for the exhaust link pipe. The bodywork was reshaped to comply with changing aesthetic tastes.
Developed mostly for younger Japanese riders, the 400 cc (24 cu in) engine still had enough power to drive the bike up to a speed-limited 180 km/h (110 mph). The inline four cylinder engine produces pleasing power anywhere in its rev range, and the bike is light and relatively easy to control. Outside the Japanese domestic market the CBR400RR was available only as a grey market import. The small capacity of the engine and manageability of the whole package makes this bike a favourite of new riders from all areas where the bike is available.
The DOHC cam gear train engine from the NC23 was later used in the NC29 and the CB400F Honda CB-1, aka NC27, a naked bike that is credited with inspiring the popular Honda 'Hornet' range. However the NC27 bears little mechanical resemblance to those machines and is probably the first true factory streetfighter.