Honda CB400SF motorcycles use frames of two modifications - NC31 and NC39. The frame is welded from thick-walled steel pipes, reinforced with gussets, and is a carrier for all components and assemblies of the motorcycle. The frame consists of a front, so-called duplex part with a steering column, an upper carrier tube, lower tubes with engine mounting elements and a rear part, in which the rear suspension pendulum, rear shock absorbers, driver and passenger footrests are mounted. The steering column uses ball bearings.
Various hinged elements are installed on the frame, allowing you to mount the body elements and mechanisms of the motorcycle. The swingarm of the rear suspension is made of aluminum alloy and is attached with an axle to the bushings at the rear of the frame. At the bottom of the frame there are fasteners for the side stop and the center stand.