Beta Enduro RR 350 2015 Workshop Manual page 115

A
Valve-seat contact conditions: A) Correct; B) Incorrect - contact face damaged-; C) Incorrect - uneven width-.
D
Positioning of contact area: D) too high; E) too low
Geometric features of valves seats.
Taking the valve out, the paint will be missing in the
contact zone. Its width must not be greater than the
following service limit:
Width service limit of valve seat contact zone:
1,9 mm.
The contact zone can principally take on three diffe-
rent appearances, as shown in the figure:
A - correct;
B - incorrect (contact face damaged);
C - incorrect (uneven seat width).
B
Also check the correct positioning of the contact area.
It must be neither higher (case D) or lower (case E).
Should the incorrect conditions described above oc-
cur, the valve seats must be rectified, respecting the
conditions carried in the following drawing.
E
If the valve seats are beyond recovery, replace the
cylinder head.
C
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