Abstract: A motorcycle engine comprising an engine housing, a crankshaft mounted for rotation within the housing, a camshaft mounted for rotation within the housing, a flexible element (e.g., a chain) coupling the camshaft to the crankshaft, and a tensioner mounted adjacent the flexible element. The tensioner includes a support member, a shoe made of a polyimide polymer (e.g., Vespel), and a biasing member biasing the support member so that the shoe is in contact with the flexible element. The biasing member is made from a wire having a quadrangular (e.g., square) cross section. Preferably, the camshaft is supported by a cam support plate, and the support member is pivotally mounted to the cam support plate.