Function

• BMW's horizontally mounted boxer engines were originally (and remain) designed to better facilitate airflow over the cylinder heads. By mounting the engines in their motorcycles in such a way as to place the cylinders directly in the flow of air as a rider rode the bike, BMW made a logical choice for keeping the engine cool and avoiding overheating problems.
  
  

History

• BMW's horizontally-opposed, twin-cylinder boxer engine design has its origins in the Treaty of Versailles. In 1919, World War I ended and the Treaty was signed. German companies were forbidden to manufacture airplanes as a stipulation of the treaty; therefore, BMW needed to find something else to build. BMW's head designer, Max Friz, designed the first boxer engine about four weeks after the treaty was signed. From the beginning, this design was prized because of its logical and inherent cooling properties.
  
  

Time Frame

• The BMW boxer engine has changed slightly over time, incorporating new materials and technologies as they became available. Originally, BMW boxer engines were air-cooled; modern BMW boxer engines are now only available as oil-cooled.
  
  

Features

• In addition to the cooling properties of horizontal engine mounting, owners of BMW motorcycles with boxer engines (those with R designations) also tout other benefits. Due to engine positioning, these bikes boast a favorably low center of gravity. This leads to easier handling and maneuverability when riding. BMW R-type owners also praise the ease with which they can access and work on various parts of the bike. If the bike experiences problems on the road, it is reasonably easy to pull off to the side of the road and fix the problem using simple tools.
  
  While it is by no means a regular occurrence, an incident in 2006 highlighted an unexpected feature of BMW's boxer engine: the shape is credited with saving the life of a Wales police officer involved in a high-speed chase. The officer's BMW R1150GS landed on him, but did not crush him even though he was dragged for some distance under the bike. The engine's unique shape created enough space for his body to safely rest underneath the bike without being crushed.
  
  

Potential

• Due to ever-tightening noise and pollution regulations worldwide, BMW has constantly evolved their most recognizable motorcycle engine. In 1984, they tried to phase it out; however, enthusiasts would not allow the boxer to die. As a result, BMW switched from air-cooled to oil-cooled boxer engines, and also from carburetion to fuel injection. The future of BMW boxer engines will be interesting, if their history of listening to their loyal customers is anything by which to judge.