PIAGGIO Vespa 1955, Service Station Manual, Page: 50 / 232

TIPS FOR ELIMINATING SPECIFIC FAULTS ON SOME OF THE
VEHICLE MODELS
Vehicle
Fault
Operations to carry out
a) Vespa 125
26
l ) Mod. VNA 1 Defective carburation
2) Mod. VNB 1 Overheating of engine
- Seizure
Difficult starting
In cases where the engine is not running regularl
y
due to a
faulty carburation, check the carburettor setting and that:
- The slow running jet is of 38 / l 00 mm.
- The main jet is of 72/100 mm.
- The needle valve coded
«
I 2 » is set at the 3rd notch.
- If the jets or needle valve do not correspond to those men-
tioned above, substitute; the above mentioned parts were
mounted in series from the vehicle VNA l T - 036800.
- To avoid overheating and seizure on vehicles prior to
VNB 1 T - 028200, during overhauls or in the case where
the cylinder is to be dismounted, apply the prescribed alu­
minum gasket between cylinder and crankcase ( see Spare
Parts Catalogue), instead of the preexisting part in paper,
so as to obtain a uniform engine temperature.
In cases of hand starting it is advisable mount the carbu­
rettor with starter device ( coded SI 20 / 15 C) in place
of the pre-existing type.
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