Norton 1948 “Model 18” 490 cc OHV single frame # C3 17544 engine # C3 17544CT
The Model 18 is first catalogued in 1923 and improvements resulting from the racing programme are regularly incorporated into the production bikes, yet the Model 18 retains its essentially vintage characteristics until an extensive redesign in 1931. At this time Norton’s side valve and overhead valve singles adopt the rear-mounted magneto – already seen on the ES2 – and switch to dry-sump lubrication. Norton continues to fit Sturmey-Archer gearboxes and all models – with the exception of the ES2 – use an open diamond frame. Changes between 1931 and 1939 include an additional drive side main bearing, revised cam gears, the adoption of Norton’s own gearbox and in 1938 a new cylinder head with enclosed valve gear. Production of an essentially unchanged 1939 model resumes after WW2 and for 1947 the Model 18 is updated with Roadholder telescopic forks in common with the rest of the Norton range. A cradle frame is used on all models after the war and for 1948 the engine of the two 490cc OHV models – the M18 and the ES2- is modified as to the timing gear and the overhead valve mechanism. The cam followers previously fitted have been dispensed with and are replaced by directly operating tappets. The mechanical noise has been reduced to a minimum and a new one-piece rocker box is employed. The machine we present here is a very well detailed older restoration. She comes with Smiths 140km/h speedo and bum pad.