1917,18- Harley's are now painted a patriotic olive green for the war in Europe. Harley-Davidson becomes the world's largest motorcycle manufacturer. In 1920 nearly 29,000 Harley's are sold but the depression cuts that total in half the following year. The company suffers its first financial loss due to slow sales and expansion. Production space is gained by leasing breweries that are shut down during prohibition.
Sidecars peak in popularity.
28- Motorcycles are now viewed as a luxury sales continue to decline. Front brakes are introduced on Big Twins. The great depression cripples Harley-Davidson and the motorcycle industry in general. It would continue into the seventies. Harley builds radios for its police motorcycles.