identifying an engine

[alistair]

can anyone help to identify an engine which i have recently acquired,
It has 1924 stamped on the timing chest and the number 69782  on the casing above the rear cylinder.
it is on a mounting which looks factory made and i wonder if it could be a stationary engine or small industrial power source as opposed to a motorcycle engine.
how can i tell?
any help would be appreciated.
thanks,
Alistair.

[Doug]

Alistair,

69782 would fall in the numbering range for a 1924, 2-3/4hp model. Douglas did indeed make stationary engine variants using these engines, but I do not know what numbering scheme that they used. Unlikely that they made 70k stationary engines, so I think this is a cycle engine re-purposed.

Most of the stationary engine 2-3/4hp have a oil sump and a place for a hand crank on the timing side. An example can be seen in this post:
https://www.douglasmotorcycles.net/index.php?topic=4059.msg14565#msg14565

There is another type without a sump (or I do not think it has a sump), on a larger cast aluminum base seen in this post:
https://www.douglasmotorcycles.net/index.php?topic=4059.msg14570#msg14570
While it looks like the motorcycle engine bolted in a cradle, the crankcase casting is slightly different between the two. Though I do not know if that stops you from using the motorcycle engine in one of these cradles, as the difference that I speak of concerns the top of the crankcase. 

At this link in the photo gallery is a 1925 model, that has some good pictures of the 'standard' 2-3/4hp motorcycle engine:
https://www.douglasmotorcycles.net/index.php?topic=2027.msg7344#msg7344

-Doug