Ducati Diavel Workshop Manual page 705

Cylinder head assemblies: valves - rocker arms
The assembly clearance must be:
highest measured value – lowest measured value = 0.03 to 0.045 mm;
the maximum permissible wear limit is 0.08 mm.
Change the valve guides when the ovality exceeds permissible limit or the clearance to the valve stem is outside the
tolerance range.
When you change the valve guide, you must also change the valve.
Valve guides as spare parts are available with outside diameter oversized by 0.03, 0.06 and 0.09 mm.
Change the valve guides as follows:
- heat up the cylinder head gradually and evenly up to 150 °C;
- remove the original valve guides using tool no. 88713.2842;
- allow the cylinder head to cool down and check the condition of the seats;
- choose suitable valve guides to obtain an interference fit in the cylinder head of 0.022 to 0.051 mm;
- heat up the cylinder head again and chill the new valve guides in dry ice;
- lubricate the bores in the cylinder head and install the valve guides using the appropriate service tools and in reference
to the dimensions given in the figure;
A= 22.4±0.15 mm.
B= 28.45±0.15 mm.
Hone the mating surface with a reamer.
Checking the valve
Check that the stem and the valve seat contact surface are in good condition.
There must be no pitting, cracks, deformations or signs of wear.
Warning
The valves cannot be ground.
Perform the following checks.
Measure the diameter of the valve stem at various points along the section that runs in the valve guide.