found it unable to climb the hills around Milwaukee without pedal assistance. They quickly wrote off their first motor-bicycle as a valuable learning experiment.[9]Work immediately began on a new and improved second-generation machine. This first "real" Harley-Davidson motorcycle had a bigger engine of 24.74 cubic inches (405 cc) with 9.75 inches (25 cm) flywheels weighing found it unable to climb the hills around Milwaukee without pedal assistance. They quickly wrote off their first motor-bicycle as a valuable learning experiment.[9]Work immediately began on a new and improved second-generation machine. This first "real" Harley-Davidson motorcycle had a bigger engine of 24.74 cubic inches (405 cc) with 9.75 inches (25 cm) flywheels weighing 28 lb (13 kg). The machine's advanced loop-frame 28 lb (13 kg). The machine's advanced loop-frame