Patent ID: 7971563

Claim:
An engine valve operating system in which a timing transmission chamber ( 48 ) is formed on one side of an engine main body ( 1 ) formed from a crankcase ( 2 ), a cylinder block ( 3 ), and a cylinder head ( 5 ); the timing transmission chamber ( 48 ) houses a timing transmission system ( 37 ) that provides a connection between a crankshaft ( 12 ) supported on the crankcase ( 2 ) and a camshaft ( 36 ) supported on the cylinder head ( 5 ) above intake and exhaust valves ( 29 i , 29 e ); opposite end parts of the camshaft ( 36 ) are supported by one side wall ( 5 a ) of the cylinder head ( 5 ) and a dividing wall ( 5 b ) formed in the cylinder head ( 5 ) so as to be adjacent to the timing transmission chamber ( 48 ); and a valve operating chamber ( 49 ) housing the camshaft ( 36 ) is defined between said one side wall ( 5 a ) and the dividing wall ( 5 b ), characterized in that an oil slinger ( 72 ) is disposed in the timing transmission chamber ( 48 ), the oil slinger ( 72 ) scattering lubricating oil ( 71 ) that has accumulated in a base part of the timing transmission chamber ( 48 ) to deposit the lubricating oil ( 71 ) on a lower part of the timing transmission system ( 37 ); an oil passage hole ( 75 ) is provided in the dividing wall ( 5 b ), the oil passage hole ( 75 ) guiding scattered oil that has been shaken off in an upper part of the timing transmission system ( 37 ) to the valve operating chamber ( 49 ); and an oil return passage ( 77 ) is provided in the cylinder head ( 5 ) and the cylinder block ( 3 ), the oil return passage ( 77 ) transmitting pressure pulsations generated in the crank chamber ( 9 ) within the crankcase ( 2 ) to the valve operating chamber ( 49 ) and making oil that has collected in the valve operating chamber ( 49 ) flow downward to the crank chamber ( 9 ).