No Yale motorcycle books - just an original Yale advertisement from 1914.
Early Yale Motorcycles were manufactured by Consolidated Manufacturing Company in Toledo. They were known as 'Yale-California' motorcycles since Consolidated took over the California Motor Company. The 1906 model carried the 'Yale' name and by 1909 the 'California' name was dropped.
Yale Twin MotorCycle (1914) Two-speed Yale Twin Advert with illustrations. "As Easy As A High Grade Motor Car And Infinitely Easier Than Many A Low Priced One" and "Comfortable Yale side-car Steam-line body" and "Comfortable Yale Side-Car"