Abstract: A muffler for decreasing the amount of noise of exhaust gases from a combustion engine is fluid connected with an exhaust port of an engine cylinder through an exhaust pipe. The interior of the muffler is divided into a first expansion chamber on the most upstream side, and a second expansion chamber on a downstream side thereof. The exhaust pipe is fluid connected with the muffler so as to be present within the first expansion chamber. The muffler is furthermore provided with a cooling pipe, which extends through the first expansion chamber, and a cooling air flows through cooling pipe.

Abstract: A muffler for decreasing the amount of noise of exhaust gases from a combustion engine is fluid connected with an exhaust port of an engine cylinder through an exhaust pipe. The interior of the muffler is divided into a first expansion chamber on the most upstream side, and a second expansion chamber on a downstream side thereof. The exhaust pipe is fluid connected with the muffler so as to be present within the first expansion chamber. The muffler is furthermore provided with a cooling pipe, which extends through the first expansion chamber, and a cooling air flows through cooling pipe.

Abstract: A balancer shaft of an engine includes a pair of journal portions, a first stage balance weight and a second stage balance weight. The first stage balance weight is formed between the journal portions and eccentrically arranged with respect to an axis. The second stage balance weight is formed on a center part of the first stage balance weight in the axial direction and projects outward from the first stage balance weight in a radial direction. The balancer shaft has a recess portion on the opposite side of the eccentricity direction.

Abstract: A balancer shaft of an engine includes a pair of journal portions, a first stage balance weight and a second stage balance weight, wherein the first stage balance weight formed between the journal portions and eccentrically arranged to an axis, the second stage balance weight formed on a center part of the first stage balance weight in the axis direction and projects outward from the first stage balance weight in the radial direction, and the balancer shaft has a recess portion on the opposite side of the eccentricity direction.

Abstract: To provide a four-cycle overhead valve engine wherein the breather passage is defined to avoid an undesirable increase in size of the engine as a whole and also to avoid increase in length of the breather passage, a four-cycle overhead valve engine is provided which includes a cylinder block (6), and push rods (16 and 17) for driving intake and exhaust valves (14 and 15), respectively, that are mounted above the cylinder block (6). A breather passage (28) connecting a crank chamber (27) and a rocker arm chamber (31) with each other is made up of a first passage portion (28A) defined in the wall of the cylinder block (6) at a location adjacent a flywheel (9) and the push rods (16 and 17), and a second passage portion (28B) extending from one side adjacent the push rods (16 and 17) in a direction away from the push rods (16 and 17). A check valve (34) for the breather passage (28) is disposed at a junction between the first and second passage portions (28A and 28B).

Abstract: To provide a breathing device for an internal combustion engine, wherein the structure around the check valve is simplified so that the engine as a whole can be manufactured compact, the breathing device includes a check valve (34) for fluid connecting, a crank chamber (27) and a rocker arm chamber (31) in the combustion engine. The check valve (34) is disposed in a head gasket (35) that is interposed between a cylinder block (6) and a cylinder head (7). The check valve (34) is in the form of a reed valve separate from the head gasket (35) and is supported by the head gasket (35) by means of a rivet (36).

Abstract: To provide a four-cycle overhead valve engine wherein the breather passage is defined to avoid an undesirable increase in size of the engine as a whole and also to avoid increase in length of the breather passage, a four-cycle overhead valve engine is provided which includes a cylinder block (6), and push rods (16 and 17) for driving intake and exhaust valves (14 and 15), respectively, that are mounted above the cylinder block (6). A breather passage (28) connecting a crank chamber (27) and a rocker arm chamber (31) with each other is made up of a first passage portion (28A) defined in the wall of the cylinder block (6) at a location adjacent a flywheel (9) and the push rods (16 and 17), and a second passage portion (28B) extending from one side adjacent the push rods (16 and 17) in a direction away from the push rods (16 and 17). A check valve (34) for the breather passage (28) is disposed at a junction between the first and second passage portions (28A and 28B).

Abstract: To provide a breathing device for an internal combustion engine, wherein the structure around the check valve is simplified so that the engine as a whole can be manufactured compact, the breathing device includes a check valve (34) for fluid connecting, a crank chamber (27) and a rocker arm chamber (31) in the combustion engine. The check valve (34) is disposed in a head gasket (35) that is interposed between a cylinder block (6) and a cylinder head (7). The check valve (34) is in the form of a reed valve separate from the head gasket (35) and is supported by the head gasket (35) by means of a rivet (36).