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 dataTiming system
Central external cover
Air filter
Horizontal cylinder timing belt cover
Screw
Filter support
Screw
Washer
Nut
Tensioner pulley assembly
Circlip
Camshaft pulley
Tensioner pin
Idler pulley assembly
Timing belt
Nut
Key
Spacer
Camshaft pulley
Driveshaft pulley ...
Spark plugs replacement
Check the colour of the ceramic insulation around the central electrode:
an even, light brown colour indicates the engine is in good condition and
running at the right temperature.
Inspect the centre electrode for wear and check spark plug gap, which should be:
0.8+/-0.1 Mm.
Important
...
Removal of the movable tensioner/timing belt
Loosen the nut (8) and remove the washer (7) and the tensioner pulley (9)
from the pin (12) on the cylinder head.
Remove the timing belt (14) from the horizontal cylinder assembly.
Important
If the belts are to be re-used, mark the direction of rotation with an
arrow and also mark the cylin ...