Engine and frame numbers

Engine number should be stamped on the LH crank-case, just below the barrel join.

Frame number is stamped on the RH frame member, on the spar that the rear footrest bolts onto.

Sometimes its on the little gusset

Birmingham bikes - Large stamps on engine, smaller (hence deeper) on frame in one of two positions on the r/hand side:

On London (Plumstead) built bikes - the fame stampings are larger (hence shallower) and only appeared in one place:

Electras (only built in London) had their own numbering system - see previous reply. Jubilees & Navigators followed the Norton numbering system.

Its because of this, the NOC cannot help with Electra numbering system enquiries (for DVLA, for example) as the AJS & Matchless OC has retained the factory records.

Some examples attached of the 3 variants. Enjoy.