The founders of Harley Davidson were William Harley with Arthur and William Davidson.There first motorcycle was rolled out in 1903.This motorcycle was nothing more than a bicycle frame painted gloss black with a single cylinder engine.They had not thought about manufacturing but family and friends interest,they decided to give it a try.The next year they built 2 more with the words HARLEY DAVIDSON MOTOR COMPANY on the fuel tank.In 1905 they sold 8 motorcycles, in 1906 this jumped to 50 motorcycles.Having seen what the younger brothers were doing the eldest brother William A. Davidson joined in and production rose to nearly 150 cycles in 1907.  These original engines were only 10.2 cubic-inch each was handmade and would put out about 2 horsepower.In 1911 these engines were improved on with the addition of mechanically actuated valves and a belt tensioning system.1912 was the introduction of one of the industries first clutches, chain drive in 1913, a two speed rear hub in 1914 and finally a three speed transmission.1912 the v-twin grew from 50ci to 61ci, in 1921 a 74 ci version was built.      



          These engines were introduced in 1929.They were 45ci v-twin engines.This is one of Harley Davidson’s longest lived engine designs lasting until 1973 in three wheeled service cars.During World War II these  engines  were used in military motorcycles and they were the basis for Harley’s racing bikes.The 45 ci was followed by two larger versions a 74ci and 80ci.But neither had the reputation for reliability like the good ol’ 45.   

        The biggest problem Harley Davidson had with the 45 was the timing it was released.A couple months after it’s debut the stock market crashed October 29,1929.Harleys sales suffered dropping from 21,000 in 1929 to less than 4,000 in 1933.

       As the thirties wore on sales improved along with the economy, So Harley began producing another engine 74-cid flathead v-twin.Aroud this time Harley also began production on another engine the 30.50-cid single flathead.These replaced the overhead-valve 21cid known as peashooters in 1930. Then in 1932 Harley offered its first three wheeled service car.This was an effort to increase sales other vehicles built at this time were special police motorcycles and a special street painter to lay down the center stripes on streets.Another  upgrade to this engine was the creation of the 80ci model.Engineers began working on anther V-Twin in 1931 this design was not completed until 1936 we know it as the KnuckleHead.But even after the Knuckle was introduced Harley continued to build Flatheads thru the mid fifties and the service cars in 1973.