APRILIA TUONO R FACTORY 2007 Service Station Manual page 150

Engine
•
If the faying surface on the valve is too
high: Grind valve seats to 35° with a
valve grinding device.
•
If the faying surface on the valve is too
low: Grind valve seats to 55° (intake)
or to 80° (outlet) with a valve grinding
device.
Grind valve sears to 45° with the valve grinding
device to remove any rough section or irregularity
on the seat and bring the valve seat width to fall
within the following values:
Intake valve A: contact mark (8): 1.0 ÷ 1.4 mm
(0.039 ÷ 0.055 in)
Outlet valve B: contact mark (9): 1.25 ÷ 1.55 mm
(0.049 ÷ 0.061 in)
After grinding the seat apply the grinding paste for valves.
Slightly press and turn the valve.
EXCESS PRESSURE COULD DAMAGE THE VALVE SEAT.
TO AVOID IRREGULAR WEAR, CHANGE THE ROTATION ANGLE.
DO NOT LET PASTE INTO THE GUIDES.
AFTER APPLYING THE GRINDING PASTE FOR VALVES, CLEAN OFF ANY RESIDUE FROM THE
CYLINDER HEAD, THE CYLINDER AND THE VALVE.
ENG - 150
TUONO R_FACTORY