Irish Motorcycle Racer Charles B. Franklin, Designer of the Indian Scout & Chief

Franklin’s Indians looks at the life of Irish motorcycle racer and Indian Motocycle designer Charles B. Franklin

| March/April 2012

A tuner/developer and a factory engineer, Charles B. Franklin was also the first great Irish motorcycle racer. He competed in the Isle of Man TT seven times between 1908 and 1914, placing second in 1911, his best finish. On a single day at Brooklands in 1912, Franklin set world records for two, four, five and six hours, and became the first man to ride 300 miles in less than 300 minutes.

English motorcycle historian Peter Hartley reported that Franklin discovered the so-called squish principle in 1914, as he reshaped the combustion chambers of an inlet-over-exhaust Indian F-head racing twin. The idea was to reduce the combustion chamber volume above the piston to near-zero, starting from the remote side and extending to the piston center, then to incline the chamber “roof” upward as it extended into the side “pocket” where the overhead inlet valve and upside-down exhaust valve were situated; combustion actually started here. This was about five years before England’s Harry Ricardo patented the principle following his research into side-valve engines during WWI. In 1914, Franklin’s racing acclaim and proven engineering experience were factors in his appointment as manager of Indian’s Dublin distributorship.

In 1916, Charles B. Franklin joined the engineering staff of Indian Motocycle in Springfield, Mass. Franklin became the chief engineer at Indian, designing the immortal Indian Scout, which debuted as a 1920 model. On the racing front, Franklin continued to show his mastery of engine preparation, and by 1926 his racing side-valve Indians were running faster than either the Harley-Davidson or Indian eight-valve overheads.

When a 750cc (45ci) version of the Scout was introduced as a 1927 model, it exceeded expectations. Although 25 percent larger than the 600cc Scout that preceded it, the 45 produced in excess of 25 percent more torque and horsepower. The Scout 45 simply breathed better than the smaller version, and adept dealers were able to make their 45s faster than the hottest local Harley 74.



Franklin’s greatest creation was the 1928-1931 Series 101 Scout. Their increased wheelbase and lower saddle mounting gave the 101s remarkable stability and agility.

Unfortunately, Franklin became seriously ill in late 1931. The authors of the Franklin biography make no claim regarding Franklin’s degree of involvement with the 1932 Scout Pony 500cc twin and the derivative 1933 Motoplane 750cc twin. But it seems likely that Franklin established the general layout in which the engine/transmission was a stressed member in what Indian called the “keystone” frame and what the British called a “diamond” frame. The choice of this very un-Indian layout remains a mystery, as Charles B. Franklin died in October 1932, having never discussed Indian engineering matters with outsiders. He was a private man and may not have publicly commented on any Indian engineering matters even had he lived much longer.






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