Lastly, the type of engine (displacement and configuration) is governed by a set of guidelines that attempts to balance competition by allowing, for example, air/oil-cooled twin-cylinder engines a larger displacement limit.
Lastly, the type of engine (displacement and configuration) is governed by a set of guidelines that attempts to bring technical diversity to the class by establishing technical limitations that allow different technologies to remain competitive. For example, air/oil-cooled twin-cylinder engines are allowed a larger displacement limit.