Abstract: An exhaust apparatus for controlling the timing of exhaust operation in two-cycle engines including a pivotally mounted plate positioned in a recess in the upper surface of an exhaust passage. The plate includes a shaft bearing portion above the pivot axis of substantial strength. A plate extending from that bearing portion is reduced in thickness with a upwardly extending ridge at the outer end thereof to define a control surface and sealing mechanism for the plate. The cooperation between the exhaust port and the end of the valve body may be arranged for maximum sealing and maximum wall thickness of the surrounding port.

Abstract: A two-cycle engine includes a port timing control device for varying a timing of the opening of an exhaust port by a piston. The port timing control means includes a first valve mounted within an exhaust passage adjacent to an upper end of the exhaust port and having a port timing control surface, a second valve mounted on a cylinder block between a cylinder head and the first valve and having a closure surface, and an urging member acting on the second valve to always urge it against the first valve. The first valve is operable to be angularly moved about an axis generally perpendicular to the axis of a cylinder into and out of an extended position where the control surface is disposed slightly below the upper end of the exhaust port to close a part of the exhaust port. The second valve is movable along a generally straight path into and out of an extended position where the closure surface closes that portion of the exhaust port lying between the upper end of the exhaust port and the first valve.

Abstract: A device for introducing air into the exhaust system of a V-type motorcycle engine. The device includes an air manifold advantageously positioned within the V of the engine with passages extending to each exhaust passage adjacent each exhaust port. A control valve run by vacuum admits air to the manifold while reed valves control the passageways to each exhaust passage. The portion of the passage extending through the cylinder head in one embodiment includes a simple bore in tangential intersection with the exhaust passages. A pipe is positioned within the bore which has nozzles therethrough for proper introduction of air to the exhaust.

Abstract: An exhaust gas cleaning device of an internal combustion engine wherein a secondary-air supply passage is connected to an exhaust system of the engine and a reed valve means is provided in the intermediate part of the secondary-air supply passage for opening in response to the pulsation pressure of the exhaust gas in the exhaust system to supply secondary air for cleaning exhaust gas to an exhaust passage and burn the unburnt components present in the exhaust passage thereby to clean exhaust gas. A desired amount of secondary air is supplied to each of a plurality of exhaust systems so that the exhaust gas cleaning efficiency as well as the reliability and durability of the reed valve means are improved and moreover a good external appearance is obtained.

Abstract: A catalytic converter having two spaced catalyst elements is positioned between a front muffler and a rear muffler. Chrome plating of the mufflers does not adversely affect performance of the catalyst elements because welding of the mufflers to opposite ends of the catalytic converter is accomplished after the chrome plating step. Masking of the joinder areas before plating avoids blow holes at the welds, and silver paint is later applied to the areas which were masked. The catalytic converter is constructed by simultaneously pushing the two catalyst elements and flanged sleeves into opposite ends of the catalyst casing, using tapered guide rings and flanged pusher bars to squeeze peripheral cushions into place within the catalyst casing and around each of the catalyst elements. Welding electrodes are employed in combination with the flanged pusher bars to spot weld the catalyst casing to the flanged sleeves.

Abstract: A catalytic converter effective to prevent damage or breakage of a catalytic element for improved durability. A catalytic element is housed in a casing and a pair of first and second end members are fitted into the opposite end portions of the casing so as to support the opposite end portions of the catalytic element via first and second end cushions. The first and second end cushions have, when in a free state, a rectangular cross section and inner diameters gradually increasing toward the catalytic element. The first and second cushions are compressed, when the catalytic converter is assembled, by the first and second end members to be fitted and held at their respective inner end portions between the inner circumferential surface of the casing and the outer circumferential surfaces of opposite end portions of the catalytic element.

Abstract: In an exhaust gas cleaning system wherein secondary air is supplied into the exhaust passage to re-burn the unburnt harmful component in the exhaust gases, a secondary air controlling apparatus for an internal combustion engine is provided. At deceleration of the vehicle, secondary air is interrupted from being fed into the exhaust passage, and is introduced into the intake passage to prevent after-burning in the exhaust cleaning system. When the ignition key is switched off, secondary air is fed into the intake passage to prevent the unburnt gas from flowing out into the exhaust passage. This effect is attained by using a valve operated in response to the negative pressure in the intake pipe to protect the exhaust gases cleaning system and to clean the exhaust gases.

Abstract: An expansion-type muffler for internal combustion engines, interposed in an exhaust system, and provided with a chamber with a substantial volume. The chamber communicates with the up-stream and down-stream sides of the exhaust system. A plate member is connected with an inner wall of the muffler body, and is provided in the body so that all of the connecting points between the plate member and the inner wall are not disposed in the same plane perpendicular to the longitudinal axis of the muffler body.

Abstract: A muffler for internal combustion engines having the interior of an expansion chamber sectioned by a porous plate through which an exhaust inlet pipe is extended. The inlet pipe is closed at its down-stream end and is provided with many perforations in that part of the inlet pipe positioned in the expansion chamber. Such perforations permit the inlet pipe to communicate with the interior of the expansion chamber in the muffler.

Abstract: A muffler having a sealed diffusion chamber provided at its front end with an inlet port of a cross section smaller than that of the diffusion chamber. Within the diffusion chamber there is an outlet pipe having a closed front end disposed a fixed distance from the inlet port. The rear end of the outlet pipe communicates with the atmosphere. The walls of the outlet pipe are perforated to permit communication between the diffusion chamber and the interior of the outlet pipe.