The desmodromic valve engine, widely used by Ducati, uses cams and levers to close its valves in place of what conventional mechanism?
Ducati 749 The Ducati 749 is a 90° V-twin Desmodromic valve actuated engine sport bike built by Ducati Motor Holding between 2003 and 2006. Designed by Pierre Terblanche, the 749 was available as the 749, 749 Dark, 749S, and 749R. It shared many of its parts with the 999, with the exception of a slightly smaller 180/55 profile rear tire, smaller cylinders, and different cylinder heads, giving it a smaller displacement of 748 cc. This smaller engine is higher revving and produces a lower peak horsepower than the larger engine used in the 999. The 749S model, like the 999, incorporates features rarely found on production motorcycles, including adjustable rake (23.5° or 24.5°) and five-position adjustable rearset mounts.
Hydraulic circuit A hydraulic circuit is a system comprising an interconnected set of discrete components that transport liquid. The purpose of this system may be to control where fluid flows (as in a network of tubes of coolant in a thermodynamic system) or to control fluid pressure (as in hydraulic amplifiers). For example, hydraulic machinery uses hydraulic circuits (in which hydraulic fluid is pushed, under pressure, through hydraulic pumps, pipes, tubes, hoses, hydraulic motors, hydraulic cylinders, and so on) to move heavy loads. The approach of describing a fluid system in terms of discrete components is inspired by the success of electrical circuit theory. Just as electric circuit theory works when elements are discrete and linear, hydraulic circuit theory works best when the elements (passive component such as pipes or transmission lines or active components such as power packs or pumps) are discrete and linear. This usually means that hydraulic circuit analysis works best for long, thin tubes with discrete pumps, as found in chemical process flow systems or microscale devices.