APRILIA STRADA 660 Service Manual page 65

ENGINE
• Using a dynamometer, measure the compressed spring
force with installed spring length of 35.00 mm (1.38 in).
In case reading is not within indicated values, change
valve spring.
Compressed valve spring force (installed):
171 - 197 N at 35.00 mm
(17.44 - 20.09 kg at 35.00 mm,
38.44 - 44.29 lb at 1.38 in).
•
Resting on a reference surface and using a square,
measure valve spring inclination (H). In case reading is
not within indicated values, change valve spring.
Maximum spring inclination:
2.5 ° /1.8 mm (2.5 ° /0.071 in).
3 - 38
MY 660