Image Number 4 for United States Patent #6708659.
An engine has a combustion chamber. An air induction system communicates with the combustion chamber through an intake port. An exhaust system communicates with the combustion chamber through an exhaust port. Intake and exhaust valves move between an opening position and a closing position of the intake port and the exhaust port, respectively. A camshaft actuates either the intake valve or the exhaust valve. The camshaft extends generally vertically. A camshaft cover member encloses the camshaft together with an engine body of the engine. The camshaft cover member defines a slot through which a tool can pass. The tool can prevent the camshaft from rotating.