Dry-sump lubrication type four-stroke cycle engine

A dry-sump lubrication type four-stroke cycle engine having a crankcase provided with a crankshaft chamber containing a crankshaft in its front part and a transmission chamber in its rear part, a generator chamber on one side of the crankcase in an axial direction of the crankshaft, and a clutch chamber on the other side of the crankcase;

• wherein the crankshaft chamber and the transmission chamber are separated by a partition wall of a predetermined height to form an oil reservoir chamber in a lower part of the transmission chamber,
• an auxiliary oil reservoir chamber is formed in a lower part of the clutch chamber so as to communicated with the oil reservoir chamber,
• a suction chamber is formed integrally with the crankcase under a crankshaft chamber bottom wall defining a bottom of the crankshaft chamber so as to communicate with a suction port of a scavenging pump of the engine,
• the suction chamber opens into the crankshaft chamber through a first suction hole formed in the crankshaft chamber bottom wall and opens into the generator chamber through a second suction hole formed in a wall defining a bottom of the generator chamber, and
• the scavenging pump pumps up oil from the suction chamber and discharges oil into the oil reservoir chamber or the auxiliary oil reservoir chamber.