VESPA GTS Super 125 i.e. Service Station Manual page 24

Characteristics
- Insert the valves into the cylinder head.
- Alternatively check the intake and exhaust
valves.
- The test is carried out by filling the manifold with
petrol and checking that the head does not ooze
through the valves when these are just pressed
with the fingers.
Measure the camshaft bearing seats and rocking
lever support pins with a bore meter
Specification
Bearing "A"
Bearing "B"
Bearing "C"
- Measure the unloaded spring length.
Characteristic
Standard length
40.5 mm
Allowable limit after use:
39.7 mm
- Clean the valve seats of any carbon residues.
- Using the Prussian blue, check the width of the
impression on the valve seat "V".
Characteristic
Admissible limit:
1.6 mm
- If the width of the impression on the valve seat exceeds the specified limits, replace the cylinder head.
CHAR - 24
HEAD BEARINGS
Vespa GTS Super 125 i.e.
Desc./Quantity
37 +0.025
20 +0.021
12 +0.018