APRILIA MXV 450 - Page 108

•
Remove the spring of valve (6) and the
corresponding upper cap (5).
•
Remove the valve.
•
Remove the stem oil seal of valve (3)
and the lower cap (4).
See also
Removing the decompression system
Removing the overhead camshaft
Removing the rocker arms
Checking the overhead camshaft
CAMSHAFT TOOTHED WHEEL CHECK
•
Check that the camshaft gear works properly: if it is damaged or does not move smoothly,
replace the timing chain and the camshaft gear.
CAMSHAFT LOBES
•
Check that they do not show blue colouring, cracks or scratches; otherwise, replace the
camshaft, gear and chain.
•
Fasten the camshaft in horizontal po-
sition, as shown in the figure, and make
it spin to check the eccentricity with a
dial gauge; if necessary, replace the
part.
Characteristic
Camshaft eccentricity - maximum limit
0.05 mm (0.0020 in)
Checking the rocker arms
ROCKERS AND ROCKER SHAFTS CHECK
NOTE
THE FOLLOWING PROCEDURE APPLIES TO ROCKERS AND ROCKER SHAFTS.
Engine MXV 450
ENG - 108