The engine is fitted with an aluminum alloy cylinder head, which carries the camshafts, valves and spark plugs. The cylinder head is cast as a single entity, to which various components are permanently added after machining.
A silent-running cam chain drives the twin-overhead camshafts, which run directly in the cylinder head without additional bearings. The chain is tensioned by a spring-loaded device fitted to the cylinder head, and is guided by two Teflon-coated rubber-faced blades. Valve clearances are adjusted by changing variable thickness shims that sit between the camshaft and valve tappet bucket. The valves are fitted with single, symmetrical valve springs. Both the tip and seat face of the valves are hardened to give a long service life. Due to assembly methods used, the valve seats and valve guides cannot be replaced.
Oil is supplied to the cylinder head by an internal passageway inside the engine. Once it arrives at the cylinder head, it is passed through a restrictor, and is then delivered to the camshaft bearing journals along grooves in the cam ladder. The camshaft lobes are splash fed by oil coming from the camshaft journals.