Motorcycles in general and medium-priced old cafe-racers used mainly for timekeeping, are electronic watches with quartz movements. Expensive collectible watches, valued more for their elaborate craftsmanship, aesthetic appeal and glamorous design than for simple timekeeping, often have purely mechanical movements and are powered by springs.
I must therefore warn that well-known character, the general reader, that I am here embarked upon a most distasteful business: taking down the picture from the wall and looking on the back.