Sakakibara also encouraged Honda’s interest in the world of motor sports. Motor sports in Japan goes back to the early years of the Taisho Era (1912–1926), around the beginning of World War I. It began with motorcycle racing but soon developed into full-scale car racing, which became popular back in the 1920s.
That was not all, because the automobile magazines carried amazingly detailed information about motor sports abroad. Japanese motor racing fans were aware, for example, that the Isle of Man Tourist Trophy (TT) was the world’s greatest two-wheel event, and that the greatest car races were the Grand Prix (GP) and the Le Mans 24-hour in Europe, and the Indianapolis 500 in the United States. Of course, Honda knew this as well.
In 1928, the automobile magazine "Motor" contained an advertisement for Art Shokai that mentions the Hamamatsu branch managed by Honda. The automobile and motorcycle magazines of this period contained detailed articles about the Isle of Man TT Races.
In 1923, the company started to make racing cars under Sakakibara’s leadership with the help of his younger brother Shin’ichi, Honda and a few other students. The first model was the "Art Daimler," fitted with a second-hand Daimler engine. The second was the "Curtiss." This car is still preserved in the Honda Collection Hall in operable condition. This consisted of a second-hand engine from an American Curtiss "Jenny" A1 biplane fitted to the chassis of a Mitchell, an American car. Mr. Honda was particularly keen to help with the development of this special machine, encouraging Sakakibara with his skill in fabricating spare parts. On November 23, 1924, the "Curtiss" took part in its first race at the Fifth Japan Automobile Competition and won a stunning victory with Shin’ichi Sakakibara as driver and Soichiro Honda as accompanying engineer. After that experience the seventeen-year-old Honda would never lose his enthusiasm for motorsports.
At the age of twenty, Mr. Honda was called up for military service, medically examined and found to be color blind. Thanks to this diagnosis he managed to avoid spending any time in the military.