MV Agusta 2008 F4 312RR 1078, Workshop Manual

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Cylinder kit
C
Guide valve installation
Assemble an oversized valve guide as follows:
Oil the external valve guide surface.
Slowly and evenly heat the cylinder head up to 150°.
If necessary cool the valve guides with (N2) nitrogen
liquid; or dry ice.
Insert the valve guide using the special n° 8000A2385
tampon up to the stroke and let rest until the tempera-
ture has stabilized.
Check to be sure the valve slides freely in the valve
guide otherwise coat it with a 4,5 H7 reamer or broach
N° 8000A2625.
Valvola
The stem diameters must not fall below:
4,485 -3/100 mm inlet
4,475 -3/100 mm exhaust
The width of the sealing surfaces should fall in the
range 0.7 - 1.2 mm (see figure).
Check to be sure that the stem and the surface in
contact with the valve slots are in good condition. No
traces of pitting, cracking, deformations or traces of
wear should appear. Verify that the stem is perfectly
rectilinear.
Plane
αα
(coinciding
axial valves exhaust)
Plane
ββ
(coinciding axial
valves inlet)