Firstly, the current situation surrounding a motorcycle market in the world and the category of motorcycles are outlined. After overviewing the major characteristics of motorcycle engines, for example, an engine revolution, a lightweight design, a cooling system and an engine oil, then picking up major components of the motorcycle engine, component technologies and its tribological issues are described. As actual components, a Ti made valve lifter, a monolithic Al cylinder, a connecting rod and a crank pin are covered. The function required for the each components and the tribological issues occurring on a contacting and/or sliding surfaces to be solved are explained. Then materials and surface treatments which is applied for the components are introduced.