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 dataRemoval of the crankshaft/connecting rods assembly
After separating the crankcase halves, withdraw the crankshaft (6) complete
with connecting rods (2).
...
Removal of the exhaust system
Remove the silencer, as described in the paragraph "removing the silencer" of
this section.
Loosen the screws (28) and remove the exhaust by-pass valve cover (27).
Turn the exhaust valve pulley (a) to facilitate the throttle cable (25)
output.
Release the end fitting (b) of the cable ...
Reassembly of the clutch-side crankcase cover
Fit the plug (14) and the gasket (13). Fit the plug (17) and the gasket (15).
If the bush has been replaced, fully seat the new bush (7) in the slot in the
cover using a suitable drift and a press.
If the sealing ring (8) needs to be renewed, fit the new seal into the crankcase
cover, po ...