Spark Plug - APRILIA SR 50 - 1998 Manual

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SPARK PLUG

Carefully read p. 39 (MAINTENANCE).
Check the spark plug after the first 500 km
(312 mi), and successively every 4000 km
(2500 mi) or 12 months.
Periodically remove the spark plug and clean
it carefully, removing carbon deposits;
change it if necessary.
To remove and clean the spark plug:
WARNING
Before carrying out the following opera-
tions, let the engine and the exhaust si-
lencer cool down until they reach room
temperature, in order to avoid burns.
Take off the spark plug cap (1).
N Remove all the dirt from the base of the
spark plug, then unscrew it with the span-
ner you will find in the tool kit and extract
it from its seat, taking care that neither dust
nor other substances enter the cylinder.
N Make sure that there are neither carbon
deposits, nor corrosion marks on the elec-
trode and on the central porcelain part; if
necessary, clean them with the special
cleaners for spark plugs, with an iron wire
and/ or a metal brush.
N Energetically blow some air, in order to
prevent the removed residues from get-
ting into the engine. If the spark plug has
crackings on the insulating material, cor-
roded electrodes or excessive deposits,
it must be changed.
N Check the spark plug gap with a thickness
gauge. The gap must be 0.6 - 0.7 mm,
0.9 mm; if necessary adjust it, care-
fully bending the earth electrode.
N Make sure that the washer is in good con-
ditions. With the washer on, screw the
spark plug by hand in order not to dam-
age the thread.
N Tighten the spark plug by means of the
spanner you will find in the tool kit, giving
it half a turn to compress the washer.
Spark plug driving torque:
20 Nm (2.0 kgm).
CAUTION
The spark plug must be well tightened,
otherwise the engine may overheat and
be seriously damaged.
Use the recommended type of spark plug
only, see p. 73 (TECHNICAL DATA), in or-
der not to compromise the life and per-
formance of the engine.
N Position the spark plug cap (1).
N Put back the inspection cover.
use and maintenance SR 50
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