The Pre-1941 Triumph Motor Cycle Pages

1931 Model NM showing the extensive lining applied with a colour option

1932 Model CD

For 1931 Triumph had a whole new range of 'Inclined'-engined machines. Triumph were late in joining the fashion, which had probably been started by BSA with their 'slopers', but Triumph's cylinders were 'inclined'! Not only the 'sloper fashion' but Triumph also incorporated the other current fashion of partial engine enclosure, and even went 'overboard' with the 'clean lines' by minimising untidy cables. This was achieved by routing cables within the handlebars until they exited at the frame headstock, to be routed unseen under the petrol tank or discretely down a fork leg. (It had been common practice for many years to exclude cables from advertisement pictures due to them giving an untidy appearance to the machine.) Not only were the cables hidden as much as possible but so also were oil pipes, for the new inclined engines had the oil reservoir housed within the crankcase and a quite complex rotating-piston pump simply transferred oil between the reservoir and the crankcase proper, and back again; a distance of maybe an inch. Initially there were four new models in this range, with a fifth added shortly after the sales catalogue was produced. The C-Series Models CN, CSD and CTT continued into 1931 along with the 2-stroke Model X and the Model NSD, which had been the forerunner of the inclined-engined machines. This brought Triumph's 1931 selection to a total of ten different models. In the following years Sports versions were added to the standard road-going models.

Brief Specifications and Variations

The five new inclined-engined models for 1931 were;

Model WO. 249cc ohv. 63mm bore X 80mm stroke.
................... This was Triumph's first 250cc design.
Model WA. 249cc ohv. 63mm bore X 80mm stroke.
................... Later in 1931. A cheaper single-port verson of the Model WO.
Model WL. 348cc s/v. 72mm bore X 85.5mm stroke.
................... A popular side-valve size.
Model NM. 343cc ohv. 70mm bore X 89mm stroke.
Model NT. 493cc ohv. 84mm bore X 89mm stroke.

All had 3-speed gearboxes, but 4-speed boxes were available as an optional extra on the Models NM and NT, and also on the other models from 1932.

The Model NT would have been capable of taking a sidecar, but the Models CSD and ND had been kept in the range as the workhorses for that task.

1932 saw the introduction of Sports versions of the Models NM and NT in the form of the Models CA and CD, respectively, while a Sports version of the Model WO appeared for 1933, designated the Model WP.

For 1931 and 1932 optional, no charge, colours were available. This was an overall colour scheme and was possible at no charge for the petrol tank no longer needed to be plated! The optional colours were Red (closer to a maroon), Blue (described as 'electric blue', and therefore unlikely to have been the Standard Triumph blue), Green and Grey.

Considering that the world was still in rescession following the 1929 Wall Street Crash in America these inclined-engined models proved to be popular, but obviously not made in great numbers due to the general shortage of money.
According to my researches to date, approximately 1,100 Models WO were made, and approximately 950 of the single-port Models WA.
I have no knowledge of any surviving Sports Models WP, and it's no use converting your Model WO or WA to make it look like one, for the specially tuned engine had a different serial number series! (A Model WP engine, only, turned up in South Australia in June 2012.)
More general ride-to-work Models WL were made, although catalogued for a year less than those above; approximately 1,600
Only around 600 Models NM appear to have been made, with Models NT selling much better at between 1,500 and 2,000.
The Sports Models CA and CD naturally sold less, with between 300 and 400 for the former and around 1,000 for the latter.

The have knowledge of these models, or parts thereof, surviving in Argentina, Australia, Austria, Belgium, Britain, Czech Republic, Denmark, Estonia, France, Germany, Holland, Italy, New Zealand, Norway, Portugal, South Africa, Sweden and the USA.

For more information you really need to read the booklet I have written on these models.

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