This early 1930’s Douglas Mastiff 750cc twin with patina, was available for sale at a recent event.
I took the video because I thought it represented an interesting part of Douglas Motorcycle history. This is a 1932 model, registered in early 1933.
VIEW VIDEO – 1933 Douglas vintage motorcycle 750cc Side Valve
In the early 1930’s Douglas were suffering from some financial pressure. They were building over-engineered, and over-complicated machines. Most of the motorcycle manufacturers were. But the financial pressure was so great at Douglas that they produced this version of the Douglas Mastiff 750cc twin (The H32) in 1932. Then, in 1933, they specified a revised version (H33) but didn’t actually produce any! In 1934, their financial situation must have improved as the Z1 750cc side valve was produced. This was the Powerflow model and had dual frame front down tubes together with an oil tank in the petrol tank.
A little bit of history on the Douglas Mastiff 750cc twin.
In 1932, they added 750cc touring model H32 or Mastiff. The Mastiff continued to use old heavyweight duplex spring forks, though girders are slightly longer to suit larger section balloon tyres.
In 1933, as mentioned, Douglas didn’t produce any of the “revised” H33 Mastiff models. The specification included: Finned intake manifold, down-draught carb, dyno over front cylinder. Instrument panel sits atop petrol tank, metal tank badges.
They produced a few other models and introduced a lightweight motorcycle for the tighter financial market. This model was the Model X 150cc 2-Stroke – Horizontal Villiers single cylinder two-stroke engine, radial fins on cylinder.
In 1934, they had re-mapped their model range to cater for a broader market. They now produced models with 150, 250, 450, 500, 600 and 750cc engines.
The Model Z1 had a 750cc side valve and was similar in appearance to the H32 model. Itwas the star of the fleet. It was destined to be the sidecar outfit motorcycle. Revisions included: redesigned cylinders and heads on the D33/E33 crankcase and an external geared oil pump. the new duplex front down tube frame made it stand out. Unlike the H32, there was no sump. Oil was stored in a petrol tank compartment. The saddle tank has a more bulbous shape, with inset instrument panel. It was also equipped with a four speed gearbox in hand and foot shift versions. The new heavy-weight lugged forks, with lower links to the outside, had a large central barrel shape spring. It was simply catalogued as Z1.
The seller of this Douglas Mastiff 750cc twin happily started the machine. It chugged away without drama and settled down to a steady beat.
Read more on the history of each model in the Douglas motorcycles range.
If you have a vintage or veteran Douglas motorcycle, it is worth joining the London Douglas Motorcycle Club, the LDMCC. It’s a worldwide organisation and there are plenty of members available to guide you through any topic on Veteran, Vintage, or post war classic Douglas motorbikes.
