Unlike American custom bike builders who hem pretty closely to air-cooled V-twins as the basis of their custom builds, on the international scene it's anything goes—usually the stranger, the better. There's no finer example of this than the annual World Championship of Custom Bike Building, which in recent years has been won using BSA, BMW, and even air-cooled Honda inline four-powered customs. This year's event, held in conjunction with the Big Bike Europe Expo in Essen, Germany, was no different. Gathering 112 machines from 23 countries, this year's entries included bikes powered by the usual American and Italian V-twins, as well as oddballs like a diesel, a Honda generator engine, and even a 1920s boat engine. Amongst competition like this, is it even surprising the overall winner featured a Moto Guzzi horizontal single?