Every NZ 350 (completed) would have been fitted with a factory identification plate (Frame plate / Typenschild) at the DKW works during the course of production. These plates are a key source of dating information for the NZ 350 series. Frames for completed NZ’s would also have the corresponding frame number impressed into the frame (or Sub-frame on early bikes). No information relating to the engine numbers for a specific bike would have been contained within the fields on the Frame plate.
The information contained within the available fields will not be discussed here in detail; Just the basic format (layout of the Frame plate), along with the addition of a chronology. This chronological description is based purely on existing bikes that the author of this article has seen himself. This information is by no means complete and I would hope to be able to update the data, as more owners submit information and photographs.
Type 1 First type
Used on the NZ 350 and NZ 250
This first type of frame plate is used from the very earliest NZ Location on Headstock: Front
Date stated on Frame plates observed: 1938 - 1940
Type 2 First type + Additional Military information
Used on the NZ 350 only (Not seen on any surviving NZ 250’s (yet) NZ 250 production stopped in 1941)
Location on Headstock: Front
Construction: Aluminium (both frame and interference plates)
Date stated on Frame plates observed: 1940 - 1941
The Additional Interference plate is always underneath the main frame plate at the base of the headstock. This Radio interference plate is also made in aluminium, note that this additional plate is stamped with a military acceptance stamp ‘Waffen Amt’.
Type 3 Comprehensive type
Used on the ‘NZ 350’and ‘NZ 350 type 1943.’ (The ‘NZ 350-type 1943’ was constructed into 1944)
Location on Headstock: Front (at first) Moved to RH side as an improvement (due to damage occurring to the Frame plate from contact with the front main suspension spring under heavy/extreme use)
Date stated on Frame plates observed: 1942 - 1944
Type 4 Final wartime variation
Used on the NZ 350-1 only
Location on Headstock: RH side
Construction: Steel (used due to shortage of Aluminium, which was reserved for the construction of other war material)
Date stated on Frame plates observed: 1944 - 1945
NZ 500 (1939-1941)
It would appear that a frame plate that is unique to the NZ 500 was used specifically for this larger machine.
Original article by Martin John Wilby.