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 dataRefitting the cylinder head assemblies
Warning
To prevent oil leaks past the contact area between cylinders and
crankcase, each time the head is removed, cylinder and
piston must be removed as well to clean the mating faces of crankcase and
cylinder and restore the spoiled gaskets and
o-rings and apply again liquid sealant (sect. ...
Removal of the rear brake disc
Remove the rear eccentric hub (sec. 7 - 13, Removal of the rear wheel
eccentric hub and rear wheel shaft).
Undo and remove the four fixing screws (13) of the brake disk to the wheel axle
and remove the rear brake disk (14).
Loosen the four screws (24) and remove the rear phonic wheel (25). ...
Disassembly of the oil pump
Hold the oil pump (1) in a vice taking care not to damage the drive gear
(12).
Warning
Make sure that vice jaws are faced with soft material.
Remove the plug (14) and extract the spring (16) and by-pass valve (17).
Check the condition of the above components.
Remove the circlip (6) ...