The bike is powered by a two-stroke, RC-valve equipped, single-cylinder engine with a redline at 11,000 rpm.

Following the success of the NS125 (an earlier model to the NSR), the NSR125 JC20 was designed and assembled by Honda Italia Industriale S.p.A. in Rome, Italy.

Grimeca was contracted to produce the aluminium cast frame (2-piece, die-cast, bolt together construction), wheels and brake assemblies.

The NSR125 JC22 is mostly of Japanese manufacture, with the engine parts and other key elements of the running of the motorbike produced in Japan, it was then assembled in Italy and supplied to its mainly European market.

The NS125 which was available as an "F" naked, or "R" fully faired is commonly mistaken as an NSR of earlier production, although shares no real parts or design similarities.