Valve Springs - APRILIA TUONO R FACTORY 2007 Service Station Manual

Engine

VALVE SPRINGS

Carry out a measurement and a visual inspection
of the valve springs for damage, distortion or loss
of tension.
Measure the spring length at release position.
Valve springs: minimum wear limit (6) 43.4 mm
(1.709 in).
Valve springs: minimum wear limit (7) 40.9 mm
(1.610 in).
VALVE SEATS - INSPECTION AND GRINDING
Clean off any combustion residues from the valves.
Apply a coat of paste for contact marks (Prussian blue) on the surfaces of the valve seats.
Insert the corresponding valve and turn it by pressing it slightly with a grinder for valves.
Remove the valve and examine the surface.
Check the valve seat width (8) (9) and the contact marks for potential wear.
Intake valve A:
contact marks (8): 1.0 - 1.4 mm (0.039 - 0.055 in)
diameter (10): 37.7 mm (1.48 in)
Outlet valve B:
contact track (9): 1.25 ÷ 1.55 mm (0.049 ÷ 0.061 in)
diameter (11): 30.3 mm (1.19 in)
CAUTION
THE CIRCULAR TRACK ON THE SURFACES OF THE VALVE SEATS AND THE VALVES MUST
BE CONTINUOUS AND WITHOUT INTERRUPTIONS.
ENG - 148
TUONO R_FACTORY