Douglas Motorcycle 2-cylinder
A Douglas dominates the 1926 magazine issue
covering the Isle of Man TT rally.
The twin cylinders were horizontally opposed, but fore-and-aft, unlike the BMW. Thus the rear cylinder was starved for air cooling, and lost some of its power when really hot.
It was the easiest-starting machine ever, and smooth and docile. I had mine only a very short time, and I cannot understand why I got rid of it so quickly.