Abstract: An engine ignition controller in which, when a transmission is set at the first speed stage, ignition timing is set on the basis of an angle advance characteristic for causing the output of an engine to be decreased. Immediately before a vehicle speed reaches a vehicle speed limit, ignition is carried out according to an ignition pattern having a misfire rate to cause an increase rate of the vehicle speed to be decreased; while, when the vehicle speed exceeds the vehicle speed limit, ignition is carried out according to an ignition pattern having a misfire rate to cause the vehicle speed to be reduced. Further, different speed limits are set for respective speed stages higher in speed stage number than a certain speed stage so that, when the vehicle speed exceeds the vehicle speed limits, ignition is carried out according to ignition patterns to cause the vehicle speed to be decreased.

Abstract: An easy method and apparatus to eliminate casting defects from composite materials of hypereutectic Al-Si alloys and improve their properties. The product composite materials with primary silicon crystals of several microns have fine honogeneous microstructures and mechanical properties comparable to similar materials produced by the conventional powder metallurgy technology. Highly wear-resistant composite materials, in which the hypereutectic Al-Si alloy and strengthening material are homogeneously mixed, can be obtained with ease. The hypereutectic Al-Si alloy and strengthening material are homogeneously mixed by stirring blades rotated at low speed. The obtained molten composite alloy rotated at high speed about a horizontal shaft in a heat-resistant vessel. The rotor rotating and stirring at high speed spatters the molten composite alloy material to break up the crystallizing out primary silicon crystals.

Abstract: An easy method and apparatus to eliminate casting defects from composite materials of hypereutectic Al-Si alloys and improve their properties. The product composite materials with primary silicon crystals of several microns have fine homogeneous microstructures and mechanical properties comparable to similar materials produced by the conventional powder metallurgy technology. Highly wear-resistant composite materials, in which the hypereutectic Al-Si alloy and strengthening material are homogeneously mixed, can be obtained with ease. The hypereutectic Al-Si alloy and strengthening material are homogeneously mixed by stirring blades rotated at low speed. The obtained molten composite alloy rotated at high speed about a horizontal shaft in a heat-resistant vessel. The rotor rotating and stirring at high speed spatters the molten composite alloy material to break up the crystallizing out primary silicon crystals.

Abstract: A saddle type vehicle for running on an uneven ground includes a swing type engine unit whose pivot is positioned before a center of the wheel base of the vehicle. The vehicle includes a lower member disposed opposite to a lower surface of the engine unit and includes a frame connected by coupling the lower member and an upper member by a bridge member surrounding a main portion of the engine unit.

Abstract: An apparatus for cooling the cylinder head of an engine including a plurality of recesses formed in the cylinder head at the position located above the combustion chambers to accumulate oil therein and covers adapted to cover the recesses. Oil accumulated in the recesses serves to cool the cylinder head and the covers inhibit oil from being scattered from each of the recesses.

Abstract: Method and apparatus for cooling the cylinder head of an engine of the type in which oil is delivered to the area located above the combustion chambers in the cylinder head and the latter is cooled by thus delivered oil. Oil introducing means through which oil is introduced into the area located above the combustion chambers in the cylinder head are disposed in the vicinity of ignition plug fitting bosses on the cylinder head whereby oil pumped up from the oil supplying device is delivered to the area located above the combustion chambers in the cylinder head through the oil introducing means.

Abstract: An apparatus for cooling a cylinder head of an engine which includes a cylinder head cover in the form of a plate adapted to fully cover an upper open surface of the cylinder head, an upper wall of the cylinder head having an insert hole for inserting an ignition plug fitting and removing tool, the insert hole being formed on an inner wall thereof with an inclined guide groove for guiding the ignition plug fitting and removing tool, an oil passage formed in the cylinder head cover, one end of the oil passage being opened at a side portion of the cylinder head cover and the other end being branched such that the branched ends extend around a plug seat in the cylinder head, a recess formed around the plug seat in the cylinder head, covers covering the recesses, and nozzles each disposed between the recesses and the other end of the oil passage with one end of each nozzle connecting with the other end of the oil passage and the other end extending into an associated recess whereby lubricating oil pumped up from

Abstract: An oil passage comprising at least one hydraulic communication means in the form of pipe which is disposed at the position located outwardly of the cylinder block of an engine so as to establish hydraulic communication between the cylinder head and the oil pan. Oil fed in the interior of the cylinder head is returned to the oil pan by way of the hydraulic communication means.

Abstract: An improved two cycle engine is disclosed which includes a subchamber which is in communication with the exhaust port with a cylindrical valve rotatably disposed therebetween. A reed valve unit is turnably supported in the inlet port to open and close the latter. The cylindrical valve is operatively connected to the reed valve unit by way of a linkage mechanism. Either of the cylindrical valve and the reed valve unit is actuated by a servomotor and the other one is actuated by the linkage mechanism. The servomotor is controlled with the aid of a control circuit so as to allow the engine to be operated at a predetermined number of revolutions.

Abstract: A compound carburetor wherein, in order that, in the course of the transit from the primary side to the secondary side, an air-fuel mixture fed to each cylinder may maintain a uniform air-fuel ratio without causing an air lock and the transit may be made smoothly and definitely, an independent secondary slow-running fuel system is provided for each cylinder and a secondary slow mixture path includes in the course a pipe connected between a carburetor part and manifold part.