Ducati - Motorcycle Design History

Motorcycle Design History

Ducati (in its various incarnations) has produced several styles of motorcycle engines, including varying the number of cylinders, type of valve actuation and fuel delivery. Ducati is best known for its V-twin engine, called a L-twin by the company, which is the powerplant in the majority of Ducati-marqued motorcycles. Ducati has also manufactured engines with one, two, three or four cylinders; operated by pull rod valves and push rod valves; single, double and triple overhead camshafts; two-stroke and even at one stage manufactured small diesel engines, many of which were used to power boats, generators, garden machinery and emergency pumps (for example, for fire fighting). The engines were the IS series from 7 to 22 hp (5.2 to 16 kW) air-cooled and the larger twin DM series water- and air-cooled. The engines have been found in all parts of the globe. Wisconsin Diesel even assembled and 'badge engineered' the engines in the USA. They have also produced outboard motors for marine use. Currently, Ducati makes no other engines except for its motorcycles.

On current Ducati motors except for the Desmosedici and 1199 Panigale, the valves are actuated by a standard valve cam shaft which is rotated by a timing belt driven by the motor directly. The teeth on the belt keep the camshaft drive pulleys indexed. On older Ducati motors, prior to 1986, drive was by solid shaft that transferred to the camshaft through bevel-cut gears. This method of valve actuation was used on many of Ducati's older single-cylinder motorcycles — the shaft tube is visible on the outside of the cylinder.

Ducati is also famous for using the desmodromic valve system championed by engineer and designer Fabio Taglioni though they have also used engines that use valve springs to close their valves. In the early days, Ducati reserved the desmodromic valve heads for its higher performance bikes and its race bikes. These valves do not suffer from valve float at high engine speeds, thus a desmodromic engine is capable of far higher revolutions than a similarly configured engine with traditional spring-valve heads.

In the 1960s and 1970s Ducati produced a wide range of small two-stroke bikes, mainly sub-100 cc capacities. Large quantities of some models were exported to the U.S.

Ducati has produced the following motorcycle engine types:

• Single-cylinder,
  • pullrod actuated, 48 cc and 65 cc (Cucciolo)
  • pushrod actuated, 98 and 125 cc
  • two-stroke, 50, 80, 90, 100, 125 cc
  • bevel actuated, spring valved: 98 cc, 100 cc, 125 cc, 160 cc, 175 cc, 200 cc, 239 cc, 250 cc, 350 cc, 450 cc
  • bevel actuated, desmodromic valved : 125 cc, 239 cc, 250 cc, 350 cc and 450 cc
  • belt actuated, desmodromic valved : 549/572 cc Supermono, only 65 made.
• Two-cylinder,
  • bevel actuated, spring valved (V-twin): 750 cc, 860 cc
  • bevel actuated, desmo valved (V-twin): 750 cc, 860 cc, 973 cc (Mille)
  • bevel actuated, desmo valved (parallel twin): 125 cc,
  • chain actuated, spring valved (parallel twin): 350 cc, 500 cc (GTL)
  • chain actuated, desmo valved (parallel twin): 500 cc (500SD)
  • belt actuated, desmo valved (V-twin): Almost all motors since 1986.
• Four-cylinder,
  • gear actuated, desmo valved (V4): (Desmosedici)
  • pushrod actuated, spring valved (V4): Prototype Apollo, only two made.