Monolithic Block and Valve Train for a Four-Stroke Engine

A four-stroke cylinder crankcase comprising:

• a monolithic cylinder head, cylinder block having a cylinder, and crankcase that includes a crank arm;
• a piston for reciprocating in the cylinder;
• a connecting rod;
• a half-crank crankshaft in the crankcase, wherein the piston is connected to the crankshaft by the connecting rod;
• an intake valve in the cylinder head and configured to open and close a fuel intake into the cylinder;
• an exhaust valve in the cylinder head and configured to open and close an exhaust outlet from the cylinder;
• a camshaft configured to actuate the intake valve and the exhaust valve;
• and
• a belt connecting the crankshaft and the camshaft.