The transition from bicycle to “motor-bicycles” was part of a similar technological change that was building around the world at the beginning of the 20th century. Engines, suspension systems and more sophisticated gearing were advancing this transition. Many Entrepreneurs wanted to get involved for reasons that included an opportunity to be involved and others simply for an income.
Initial designs for the most part used the bicycle frame as a foundation, mounted an engine connected via a leather belt to the rear wheel, added a throttle and brake mechanism, lights and off you go. A typical design was the 2 ¾ HP 1904 Advance. It’s engine design at the time was a 360cc single cylinder engine with an exhaust valve and a flap intake valve. Its top speed was 40mph. Interesting that more of these engines were sold by Advance (Norhthampton, Britain) around the world than the motorcycles.