Ducati MONSTER 821 Workshop Manual page 861

Fit the tool handgrip no. 88765.1523 in the holes of the generator cover to be able to turn the crankshaft
so that the valve on which the check is carried out is in rest position and the relevant piston at the top dead
centre.
Check the valve clearance of the head you are working on.
Checking the opening clearance
Using a feeler gauge, check the clearance between the opening rocker arm (A) and the lowest point of the
camshaft lobe (B), taking care not to compress the rocker arm return spring.
Important
Hold the feeler gauge at a distance of at least 4-5 cm from the point of measurement between cam and
rocker arm.
Important
During this operation, press on the camshaft perpendicularly to the head surface to keep it in seat.
The value must be within the prescribed ones
Reference
Valve clearance
Opening rocker arm - intake
Opening rocker arm - exhaust
If not so, remove the opening shim (4)
obtain the prescribed clearance.
Note
Opening shims measuring 2.00 to 3.90 are available as spare parts: the size is punched on the shim
(Timing
system/valves).
Assembly value
0.13÷0.18 mm
0.13÷0.18 mm
(Removing the valves), and replace it with one of suitable height to
861
Check value every 24,000 km
0.10÷0.25 mm
0.10÷0.25 mm
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