Abstract: A scavenging valve assembly is used in a carburetor. The valve assembly includes a throttle valve and a rotary air valve. The throttle valve opens and closes an air-fuel passage. The rotary air valve opens and closes an air passage and has one or more air bore(s). When the rotary air valve begins to rotate, airflow travels through the bore(s) and the size of an opening area that airflow travels through continuously increases in size.

Abstract: A scavenging valve assembly is used in a carburetor. The valve assembly includes a throttle valve and a rotary air valve. The throttle valve opens and closes an air-fuel passage. The rotary air valve opens and closes an air passage and has one or more air bore(s). When the rotary air valve begins to rotate, airflow travels through the bore(s) and the size of an opening area that airflow travels through continuously increases in size.

Abstract: A rotary throttle valve carburetor includes a body having a fuel and air mixing passage and a throttle valve movable between idle and wide open positions. A valve bore is increasingly aligned with the fuel and air mixing passage as the throttle valve is moved from idle toward its wide open position. A fuel metering needle is responsive to movement of the throttle valve so that the needle moves relative to the body in response to movement of the throttle valve. A fuel nozzle extends into the valve bore, is associated with the fuel metering needle, and has a fuel ejection passage with an effective flow area controlled by movement of the fuel metering needle relative to the fuel nozzle and includes a portion with a cross-sectional area that gradually increases in the direction of fuel metering needle movement corresponding to throttle valve movement toward its wide open position.

Abstract: A starting device for a rotary throttle valve-type carburetor enables adjustment of the quantity of air and fuel delivered to an engine to facilitate the cold start of the engine. The starting device changes the position of the throttle valve prior to starting the engine to adjust the fuel and air mixture delivered to the engine as desired to facilitate starting and initial warming up of the engine.

Abstract: A starting device for a rotary throttle valve-type carburetor enables adjustment of the quantity of air and fuel delivered to an engine to facilitate the cold start of the engine. The starting device changes the position of the throttle valve prior to starting the engine to adjust the fuel and air mixture delivered to the engine as desired to facilitate starting and initial warming up of the engine.

Abstract: A rotary throttle valve carburetor includes a body having a fuel and air mixing passage and a throttle valve moveable between idle and wide open positions. A valve bore is increasingly aligned with the fuel and air mixing passage as the throttle valve is moved from idle toward its wide open position. A fuel metering needle is responsive to movement of the throttle valve so that the needle moves relative to the body in response to movement of the throttle valve. A fuel nozzle extends into the valve bore, is associated with the fuel metering needle, and has a fuel ejection passage with an effective flow area controlled by movement of the fuel metering needle relative to the fuel nozzle and includes a portion with a cross-sectional area that gradually increases in the direction of fuel metering needle movement corresponding to throttle valve movement toward its wide open position.

Abstract: A starting device for a rotary throttle valve-type carburetor enables adjustment of the quantity of air and fuel delivered to an engine to facilitate the cold start of the engine. The starting device changes the position of the throttle valve prior to starting the engine to adjust the fuel and air mixture delivered to the engine as desired to facilitate starting and initial warming up of the engine.

Abstract: A starting device for a rotary throttle valve-type carburetor enables adjustment of the quantity of air and fuel delivered to an engine to facilitate the cold start of the engine. The starting device changes the position of the throttle valve prior to starting the engine to adjust the fuel and air mixture delivered to the engine as desired to facilitate starting and initial warming up of the engine.

Abstract: A throttle valve lever for controlling the rate of fuel flow in a rotary throttle valve type carburetor is proposed, wherein the throttle valve lever has increased stiffness to help prevent structural deformation due to excessive force exerted and applied to the lever over time. The throttle valve lever basically includes an oblong structure comprising synthetic resin and an oblong reinforcement plate comprising metal. The resin structure has a hole defined therethrough, which is capable of fitting around the shaft of a throttle valve of a carburetor, and also has a lever portion at one end of the resin structure. The metal plate has a hole defined therethrough, which is capable of fitting around the shaft of a throttle valve of a carburetor, and also has a lever portion at one end of the metal plate.

Abstract: A carburetor in which no deviation or change occurs in the adjusted position of a fuel regulating needle valve and when a cap for limiting the adjustment is mounted on the fuel regulating valve the cap cannot be intentionally broken or removed. A flow area of a fuel pasage of a carburetor body is adjusted by a needle valve received in a threaded hole in the body. Adjacent the threaded hole the carburetor body has a cylindrical cavity having a larger diameter than that of the threaded hole. A larger-diameter threaded portion is provided on the needle valve adjacent its head. A stop ring in contact with a shoulder in the cylindrical cavity is fitted on the larger-diameter threaded portion of the valve. A cup-shaped cap is fitted on the serrated head of the fuel regulating valve. An axial protrusion formed on the outer peripheral wall of the cap is engaged with an axial groove opening into the peripheral wall of the cylindrical cavity.