According to Official Guinness Records,
The earliest factory which made motorcycles in large numbers was opened in 1894 by Heinrich and Wilhelm Hildebrand and Alois Wolfmüller at Munich, Germany. In its first two years this factory produced over 1000 machines, each having a water-cooled 1488 cc (90.8 cu in) twin-cylinder four-stroke engine developing about 1.9 kW (2.5 hp) at 600 rpm.Although an Englishman, Edward Butler, produced a motor tricycle in 1884, the invention of the first true gasoline-engine motorcycle is generally attributed to German Gottlieb Daimler in 1885. Daimler's invention was simple: he attached a four-stroke engine to a wooden bicycle frame, which was stabilized by the addition of an extra pair of lateral wheels (not unlike bicycle 'training wheels'). A pulley connected the engine to the rear wheel. Various manufacturers sprang up soon afterwards in Europe and the United States, with perhaps the most famous motorcycle of them all, the Harley Davidson, first being offered for sale in 1904. Motorcycles were used extensively during the First World War for sending dispatches, and their popularity increased rapidly as a result.
For a complete list of 1894 records, please visit 1894 Guinness Records in Germany.