As the 1970s came to an end, BMW Motorcycles faced three problems in developing its flat-twin boxer engine further:

  • Emissions regulations being developed in the United States and the European Union meant that more control was needed over the amount of fuel entering the combustion chamber. From an engineering standpoint this was easier to achieve with more cylinders at an overall smaller displacement.
  • The market-led development of bikes was leading to the Japanese factories developing smoother and quicker machines based around a four-cylinder format.
  • Bike comparison in the media at the time was based around top speed, and a four-cylinder when fully developed created more power.

In combination, this meant that BMW’s marketing to users of a superior bike, allowing them to price at a premium, was being quickly lost, resulting in a loss of sales and market share.

At the time, BMW, Moto Guzzi and Harley-Davidson were the only major “high end” manufacturers that did not offer liquid-cooled engines. Competing brands, notably of Japanese manufacture, were touting the superiority of their liquid-cooled engines and had introduced low maintenance shaft-drive technology in a growing number of their models.

BMW needed to develop a clean burning four-cylinder engine quickly. While a flat-four engine would have been suited to their boxer tradition and experience, it would also give the appearance that they were copying Honda’s GL1000 Gold Wing

To learn more about how BMW created their legendary four-cylinder engine and the K-Bike series, click here: