Originally Posted By: Robenstein
That is a pre unit Triumph. The Triumphs did not go to a shared sump system until 1963.
I would run something like a 15w40 Diesel oil given your location. You could go over to triumphrat.net if you ever need help with the bike besides what oil to run. Lots of classic Triumph owners over there.
The unit construction Triumphs were not a shared sump system as they had separate reservoirs for engine, transmission and chaincase. The engine lubrication system was dry sump with a separate oil tank. As i recall, we ran 90 weight gear oil in the transmissions, although the manuals called for 50 weight engine oil. The usual engine oil used was 20w-50, and as I recall, this was also used in the chaincase.