0,8 ÷ 0,9 mm
0,031 ÷ 0,035 in.
A
1
3
2
4
6
7
5
4
SPECIFICATIONS - OPERATION - MAINTENANCE
EN - 25
EN
SPARK PLUG CHECK
The correct type of spark plug and electrode gap is indicated in
the “Technical data” section.
A wider gap may cause difficulties in starting the engine and
overload the coil.
A narrower gap may cause difficulties when accelerating or
idling or poor performance at low speed.
- Remove the connector (1) from the coil (2).
- Loosen the two screws (3), remove coil (2) and retaining
bracket (4), and then remove the spark plug.
NOTE: during refitting, check that the gasket (5) is correctly
positioned; the reference lug (6) must correspond with the
retaining bracket (4) gap (7)
It is very useful to examine the state of the spark plug just after it
has been removed from the engine since the deposits on the plug
and the colour of the insulator provide useful indications.
Correct heat rating:
The tip of the insulator should be dry and the colour should be
light brown or grey.
High heat rating:
In this case, the insulator tip is dry and covered with dark de-
posits.
Low heat rating:
In this case, the spark plug is overheated and insulator tip is
vitreous, white or grey in colour.
CAUTION*:
If necessary, replace the spark plug with one
of the same type and heat rating (see the
technical data section).
Apply a little graphite grease to the spark
plug thread; fit and screw the spark plug by
hand then tighten to the torque of 10÷12 Nm-
7.4÷8.9 ft/lb. Loosen the spark plug then
tighten it again to the torque of 10÷12 Nm-
7.4÷8.9 ft/lb
(1÷1,2 Kgm -
7.4÷8.9 ft/lb
).
Spark plugs which have cracked insulators or
corroded electrodes should be replaced.
