APRILIA SCARABEO 500 2008 Service Station Manual page 182

Engine
- Fit the valves into the cylinder head.
- Alternatively test the intake and outlet valves.
- The test should be carried out by filling the mani-
fold with fuel and checking that the head does not
ooze through the valves when they are just press-
ed by the fingers.
Inspecting the valve housings
- Remove any carbon deposits from the valve
seats.
- Check the width of the mark on the valve seat
«V» with Prussian blue.
Characteristic
Standard value:
1 ÷ 1.3 mm
Limit allowed:
1.6 mm
- If the width of the mark on the valve seat is larger than the prescribed limits, true the seats with a 45°
milling cutter and then grind.
- Replace the head in case of excessive wear or damage.
Inspecting the valves
- Measure the diameter of the valve stem at the three positions indicated in the diagram.
Specification
Outlet:
Specification
Outlet:
ENG - 182
STANDARD DIAMETER
Inlet:
MINIMUM DIAMETER ALLOWED
Inlet:
SCARABEO 500
Desc./Quantity
4.987 ÷ 4.972 mm
4.975 ÷ 4.960 mm
Desc./Quantity
4.96 mm
4.945 mm