Valve-operating device for engine

A valve-operating device for an engine, comprising:

• a camshaft which is disposed on one side of a plane including axes of a first valve and a second valve corresponding to one and the other of an intake valve and an exhaust valve and which has an axis substantially perpendicular to the plane;
• and
• a first rocker arm and a second rocker arm which are swingably carried on a rocker shaft disposed substantially perpendicular to the plane and through which the camshaft and the first and second valves are connected to each other, whereby the first and second valves are opened and closed by the rotation of the camshaft,
• wherein the first rocker arm comprises a first arm portion with opposed sidewalls of its base end having a U-shaped section being carried on the rocker shaft and with its tip end abutting against a head of the first valve, and a second arm portion protruding from one of the sidewalls of the first arm portion with its tip end being in sliding contact with the camshaft;
• and
• wherein the second rocker arm comprises a first arm portion with opposed sidewalls of its base end having a U-shaped section being carried on the rocker shaft inside the first arm portion of the first rocker arm and with its tip end abutting against a head of the second valve, and a second arm portion protruding from one of the sidewalls of the first arm portion with its tip end being in sliding contact with the camshaft.