The ZDB (Zweitakt-Doppelport-Block) was manufactured from 1940 to 1951. Number produced: 34,000
Specifications:
123cc single cylinder two-stroke, 5 hp, max. speed 75 km/h.
Fuel consumption: 2.4 litres per 100km.
Chassis: tubular frame, pressed metal forks, rigid rear. Drum brakes front and rear.
Models built before 1949 had the spark plug mounted at an angle in the cylinder head. There was a version had a high exhaust, and the last ZDB used the NSU Fox cylinder and a DKW RT125 piston, giving it a substantial power boost.
The ZDB 125 was superceded by the NSU Fox, which was initially produced concurrently.
Source: nsu24.de