Gilera SATURNO BIALBERO 350 Workshop Manual page 118

SPARK PLUG
Check spark plug condition; replace if overheated, fouled or worn.
Measure electrode gap; clean and adjust if out of specification.
The spark plug must be checked every 1,000 km.
Electrode gap should be 0.6 ÷ 0.7 mm. Replace plug every 8,000 km.
Warning:
The use of spark plugs with different heat ranges than recommended or
different threads may result in excessive engine damage.
TROUBLESHOOTING
No spark at spark plug:
Ignition switch in the "OFF" position.
The electrical wires are loose, broken or shorted:
Between excitation coil and ignition control unit;
Between ignition control unit and engine kill switch;
Between ignition coil and spark plug;
Between generator and ignition control unit;
Between ignition coil and ignition control unit.
Ignition coil is defective.
Ignition control unit is defective.
Excitation coil is defective.
Generator is defective.
Engine starts but runs poorly:
The following may be defective:
Ignition coil;
Pulse generator;
Ignition control unit;
Excitation coil;
High tension wire;
Spark plug.
Loose or bare wires
Incorrect advance:
Loose or badly installed flywheel or generator;
Ignition control unit defective.
IGNITION SYSTEM 17
17 - 3