The design used popular North American cruiser styling and copied features found on larger displacement cruisers and factory custom-styling. The CM125 had high handlebars, megaphone silencers, a teardrop-shaped petrol tank and a stepped seat. More chromium-plated and polished alloy parts were found on this model than on the comparable Superdream and Benly 125 models. The quality of the chrome-plated finish was such that corrosion was a problem. The ignition lock was between the instrumentation, which consisted of two binnacles, one containing a speedometer; the other, a set of three warning lights (neutral, turn, high beam). The ignition key also activated both the steering lock and the lock on the plastic tool box located under the off-side side panel. The drum brakes were actuated by a cable in front and a rod in the rear.
The engine had a duplex camchain rather than the more common inverted-tooth type. Frame numbers started JC05-50 for the 1982-5 CM125CC and JC05-51 for the 1985-6 CM125CF. The appearance of this model, greatly enhanced by its substantial-looking twin cylinder engine, meant it enjoyed particular popularity in the United Kingdom, where learner motorcyclists are by law restricted to machines of 125 cc and below until they pass their riding test and obtain a full licence. The CM125 Custom was deleted from Honda's United Kingdom line-up in 1986. It continued to be manufactured and sold in Europe and Singapore as the CM125CN (1992, frame numbers (JC05) 5500023-5505185), CM125CP (1993, frame numbers (JC05) 5600001-5608387), CM125CR (1994-1998, frame numbers (JC05) 5700001-5999999) and CM125CX (1999, frame numbers (JH2JC05A*/JH2JC05B*) XK000001-XK099999). Its continuing popularity eventually led to another 125cc custom model being introduced, the Honda CA125 Rebel.