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 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 ...
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) ...
Removal of the generator cover
Note
This operation is described for an engine removed from the frame since all
reassembly procedures are easier with the
engine on the bench.
Disconnect the connector (a) from the generator cable.
Unscrew the two retaining screws (7) of the centre cap (6) over the end of
the cranksh ...