Overhead cam shaft type engine with a starter motor

An overhead cam shaft engine, comprising:

• a cylinder;
• a cylinder head mounted to said cylinder;
• a cam shaft provided in said cylinder head;
• a crank shaft;
• a cam shaft driving mechanism disposed on a first end of said crank shaft for transmitting rotation of said crank shaft of the engine to said cam shaft;
• a crank case;
• a starter motor attached to a surface of said crank case;
• a gear train disposed on a second, opposite end of said crank shaft for transmitting rotation of said starter motor to the crank shaft, said gear train including a plurality of gears, a gear shaft axis of at least one of said plurality of gears is disposed on a same side of a plane including an axis of said crank shaft as an axis of said cylinder, and an included angle between a planar portion extending toward said gear train from said crank shaft axis in said plane and said cylinder axis is an acute angle;
• and
• wherein said crank case is divided vertically into an upper crank case and a lower crank case by a dividing plane, said crank shaft is supported by said upper crank case and said lower crank case, said plane including the crank shaft axis is said dividing plane, at least one gear shaft axis of a portion of said plurality of gears is disposed on an upper side of said dividing plane, at least one gear shaft axis of the remaining of said plurality of gears is disposed on a lower side of the dividing plane, and an axis of said cylinder is positioned on said upper side.