Ducati Monster 796 Workshop Manual page 565

Cylinder head assemblies: valves - rocker arms
Note
When you change the valve guide, you must also change the valve. The intake valve guides are in cast iron while the
exhaust ones are in bronze.
Valve-valve guide clearance
Assembly clearance: 0.03 to 0.06 mm.
Maximum permissible wear limit: 0.08 mm.
Renewal of the valve guides
To renew the valve guides (11) and (13), proceed as follows.
Heat up the cylinder head gradually and evenly up to 200 °C.
Drive out the valve guide using a suitable drift (see drawing).
Allow the cylinder head to cool down and check the condition of the seat.
Select the most suitable replacement valve guide to obtain an interference fit in the cylinder head bore of
0.022-0.051 mm; replacement valve guides are supplied in O.D. oversizes of 0.03, 0.06 and 0.09 mm complete with
lock rings.
Heat up the cylinder head again and chill the new valve guide in dry ice.
Lubricate the seat and install the valve guide so that the stop ring is located against the head, using the drift previously
used to remove the old guide.
Allow the cylinder head to cool, then ream out the inside of the new valve guide.
Overhauling the rocker arms
Check for signs of wear, grooves or chrome flaking off.
Check the condition of the rocker arm bore and shaft:
- nominal diameter of rocker arm bore: 10.040 to 10.062 mm.
- nominal diameter of rocker arm shaft: 10 to 0.005 mm.
Check the contact surfaces of the shims and the valve return collets are perfectly flat with no signs of wear.