In 1989, the Italian motorcycle manufacturer launched the Ducati 400SS, a sports motorcycle also known as the 400 SS Junior. The bike was manufactured for the Italian and Japanese markets.
Alongside the 400SS model, the manufacturer released the 300SS and 600SS versions. The 350SS was made between 1991 and 1993, the 400SS from 1989 to 1997, and the 600SS from 1993 to 1999.
The 350SS and 400SS models were developed to meet Japan's 400cc and Italy's 350cc regulations limits of the maximum displacements allowed for probationary motorcyclists. The 1994 Ducati 600SS was introduced as a cheap way to expand Ducati's range.
The Ducati 400SS was based on the larger 750SS model, sharing its frame, engine, and most other components. The most notable difference between the two machines was the two-into-one exhaust system and the single brake disc on the front.
Visually, the 400SS model packed standard features, such as a full fairing with a small windscreen, a rectangular headlight, a single seat, a steel trellis frame, a single exhaust system with a muffler mounted on the left side, and three-spoke lightweight aluminum wheels.
As for the power figures, the 1989 Ducati 400SS had its heartbeat set by a 398cc four-stroke V-twin air-cooled engine managed by a Mikuni carburetor, delivering 42 hp at 10,000 rpm and 36 Nm (26 lb-ft) torque at 8,500 rpm.