At the end of 1914 Harley-Davidson management found they could no longer ignore the growing popularity of motorcycle racing. As dangerous as they found it, company officials were also businessmen and knew success on the track would pay off in dealers‘ showrooms. A supplement to the 1914 literature outlined a made to order race bike built to customer‘s specifications. In 1915, the Motor Company would offer the first factory race bikes available to the general public.
The 1915 Model 11-K was a stripped down version of the civilian 11-E. The chassis was close-coupled by shortening the rear frame section and eliminating the 3-speed transmission instead direct gearing through a single countershaft. The front fender was eliminated and the rear fender was clipped and narrowed. Weight was reduced by eliminating the sprung seat-post, primary cover, footboards and foot controls as well as adding a single gusseted rigid fork. Fuel was contained in the right side tank and the rear of the left tank with oil being held in the front portion. The hand-oil pump was relocated to the outside of the tank to add extra capacity. The riding position was lowered by adding unique drop-style handlebars with shortened handlebar ends. Spark to the special narrow 61 cubic inch twin cylinder engine was delivered by a Bosch magneto.
A milder road version of the 11-K track racer was also offered in 1915. The Model 11-KR “Roadster” featured a chopped front fender and race fuel tanks, but retained many of the stock items such as full rear fender, footboards, sprung front fork and tool box. It was available with standard or “Drop” type handlebars. A single cylinder track version, the Model 11-K4 would also be made available to compete in the 30.50 cubic inch racing classes.