Checking The Cylinder Head - APRILIA RS 125 Euro 4 Service Manual

RS 125 - Tuono 125 - Euro 4
Inspecting the valve housings
•
Remove any carbon deposits from the valve guides.
•
Measure the inside diameter of each valve guide.
•
Measure according to the thrust direction at three different heights.
Characteristic
Intake guide - standard diameter
4.012 mm (0.1579 in)
Intake guide: Wear limit
4.020 mm (0.1582 in)
Discharge guide - standard diameter
4.012 mm (0.1579 in)
Discharge guide: Wear limit
4.020 mm (0.1582 in)
•
Replace the head if the values corre-
sponding to the width of the mark on
the valve seat or the valve guide diam-
eter exceed the specified limits.
•
Check the width of the mark on the
valve seat «V».
Characteristic
Wear limit for the width of the mark on the valve
seat "V"
•
Intake: 1.6 mm (0.0630 in)
•
Outlet: 1.8 mm (0.0708 in)
Inspecting the springs and half-cones
•
Check that the spring upper supporting
caps and the cotters show no signs of
abnormal wear.
•
Check the unloaded spring length.
Characteristic
Valve spring length:
33.24 +/- 0.25 mm (1.3086 +/-0.0098 in)

Checking the cylinder head

•
Using a trued bar, check that the head surface is not worn or distorted.
Engine
ENG - 209