The Pre-1941 Triumph Motor Cycle Pages
From Peter Cornelius - Triumph Specialist for the VMCC - of Britain.
1933 Model XO
1934 Model XO 5/5
Following the two-stroke Model X Triumph decided to produce a more
'refined' overhead valve machine, and this was logically designated the
Model XO and was catalogued for 1933; the Models X and Z being discontinued
at the same time.
With an inclined cylinder with cooling fins mounted horizontally
in line with the direction of travel, and oil recirculated from a
crankcase oil reservoir,
the little 147cc Model XO engine was a masterpiece of 'minature' engineering
at that time. This had been Triumph's smallest four-stroke engine, and
it was overhead valve 'to boot'!
Not only did the engine look good, but so did everything else
about the machine.
The original Model XO proved to be very popular and by 1934
there was also a sports version, as well as larger 174cc models.
The original 147cc versions became Models XO5, while the 174cc models were
It was a shame that it was not contined following the
introduction of Val Page's 1934 machines, and thereafter the smallest
available machine was 250cc.
Brief Specifications and Variations
Catalogued for 1933 and 1934.
1933 - Model XO. 147cc 4-stroke ohv. 56.6mm bore X 59mm stroke.
A three-speed gearbox was standard, with a four-speed box available as an
1934 - Model XO5/1. Standard model. 147cc 4-stroke ohv. 56.6mm bore X 59mm stroke.
........ - Model XO5/5. Sports model. 147cc 4-stroke ohv. 56.6mm bore X 59mm stroke.
........ - Model XO7/1. Standard model. 174cc 4-stroke ohv. 61.5mm bore X 59mm stroke.
........ - Model XO7/5. Sports model. 174cc 4-stroke ohv. 61.5mm bore X 59mm stroke.
Electric lighting, legshields and lifting handle were standard,
except on the Sports models which had no legshields.
I do not currently have enough details from surviving machines to be able to
give a more accurate estimation of production figures, but it
would appear to be between 1,500 and 2,000.
I have knowledge of surviving, or had been, Models XO in Argentina,
Australia, Britain, Denmark, Germany, Holland, Ireland, Italy,
New Zealand and South Africa. There is also one in a museum in America
but it would not have been originally sold there, due to American
restrictions on imports in order to protect their own motor cycle
For more information you really need to read the booklet
I have written which includes these models.
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