Desmodromic (type) with four valves per cylinder, operated by eight rocker arms (4 opening rockers and 4 closing rockers) and two overhead camshafts. It is operated by the crankshaft through spur gears, belt rollers and toothed belts.
Desmodromic timing system (fig. 159)

Engine
Performance dataInspection of the gear selector drum
Use a gauge to measure the clearance between fork pin and the slot on the
selector drum.
If the service limit is exceeded, determine which part must be replaced by
comparing these dimensions with those of new
components (sect. 3 - 1.1, Gearbox).
Also check the wear on the drum support pin ...
Changing the engine oil and filter cartridge
Note
This operation has to be carried out with hot engine (but turned off)
because the oil in these conditions is more fluid and
its evacuation is faster and complete.
Remove the drain plug (3) with seal (a) from the oil sump and allow the oil
to drain off.
Warning
Dispose of oil and/or fil ...
Reassembling the front footrest brackets
To reassemble the brackets (6) and (21) carry out the removal procedure in
the reverse order; tighten the screws (7) to a
torque of 25 nm +/- 10% (sect. 3 - 3, Frame torque settings).
...