MV Agusta 2008 F4 312RR 1078 Workshop Manual page 49

Maintenance of the valve slot
Check the stroke surface [A] between the valve [B] and
the slot [C] : no traces of pitting or cracks must appear.
Measure the external diameter [D] of the stroke surface
on the valve slot.
If this should appear to be too elevated it is possible to
repair the slot.
External diameter of the stroke surface of the valve
slot
Standard: exhaust 24,6
inlet 28,6
Measure the width of the stroke [E] with a varnished
gauge or with Prussian blue.
If it should turn out to be too wide, too thin or irregular
it will be necessary to repair it.
Thickness of the stroke surface of the slot
standard : exhaust, inlet 1
The repair must be carried out by milling the slots using
the appropriate monocutting milling machines at 78°
(1), 45° (2) and 17° (3).
Ten proceed with the grinding of the valves and verifi-
cation of the holding.
Remove the minimum quantity of material from the
slot.
Inlet max 0,5 mm (vertical)
Exhaust max 0,5 mm (vertical)
Verify that there is no leakage filling the inlet
and exhaust of the gas canalization.
If so, check the quality of repair with
Prussian blue.
When reassembling never use calibrated
tablets of a thickness inferior to 1,6 mm.
+0,3
mm
0
+0,3
mm
0
+0,2
mm [E]
-0,3
Cylinder kit
OPTIMAL
TOO
THIN
- 19 -
TOO
WIDE
IRREGULAR
C