A single-cylinder, four-stroke cycle, internal combustion engine arranged in an overhead valve configuration includes a first valve train and a second valve train. The first valve train includes a first cam on a camshaft, a first pushrod driven by the first cam, a first rocker arm attached to the first pushrod, and an exhaust valve driven by the first rocker arm. The second valve train includes a second cam on the camshaft, a second pushrod driven by the second cam, a second rocker arm attached to the second pushrod, and an intake valve driven by the second rocker arm. The first rocker arm is longer than the second rocker arm.