Abstract: To provide an apparatus for feeding secondary air to exhaust gas in an engine. The apparatus includes a cylinder head having an exhaust port for discharging exhaust gas from a combustion chamber and a secondary air feed passage for feeding secondary air to exhaust gas flowing through the exhaust port. The apparatus is capable of making a length of the secondary air feed passage as short as possible while preventing the permeation of exhaust gas into the secondary air feed passage. This avoids the enlargement of the entire engine, when disposing a reed valve in the engine, since the reed valve is mounted to the cylinder block. A secondary air passage includes a first passage portion extending in a straight line with one end opened toward the inner surface of an exhaust port, toward the downstream side of exhaust gas in the flowing direction.

Abstract: A seat for receiving a fuel injecting valve, is provided in an intake pipe at a portion closer to an intake port, than a straight line connecting a crossing point P, of a first and a second center lines CL, and CL, to a curved center C. of the bent pipe portion; fastening seats and for fastening the mounting member, to the intake pipe, is provided on the intake pipe, at such a position as to put the straight line between the seat and the fastening seats and; and the seat and the fastening seats and are formed in parallel to each other.

Abstract: To simplify the idle opening amount between each cylinder and simplify the structure of a throttle body, starter valves having tuning screws capable of respectively adjusting the flow amount of air supplied to the intake port of each throttle body are arranged in a line in a valve body. Due to the provision of the valve body, a joint pipe for supplying air having a flow amount is adjusted using the starter valves. The throttle bodies are connected through a bypass tube to the valve bodies such that the valve bodies are separated from the throttle bodies.

Abstract: Bypass tubes connected to intake ports of each throttle body are connected to joint pipes of a starting control valve assembly. The starting control valve assembly includes valve bodies having communication paths formed therein. The communication paths communicate with an air cleaner. First and second flow paths connect the communication paths and the joint pipes. Tuning screws are provided for adjusting the opening amount of each of the first flow paths and a shaft valve is rotatably mounted in through holes which are orthogonal to the second flow paths for collectively adjusting the opening amount of the second flow paths. Furthermore, a plurality of idle connection holes are provided in the shaft valve which all face in the same direction.