Spark Plug - APRILIA SR 50 - 2001 Manual

1

SPARK PLUG

Carefully read p. 55 (MAINTENANCE).
Check and clean the spark plug after the
first 312 mi (500 km). Change it every
2,500 mi (4,000 km).
Periodically remove the spark plug and
clean it carefully, removing carbon deposits;
change it if necessary.
To reach the spark plug:
♦
Remove the left inspection cover, see p.
71 (REMOVING THE RIGHT AND LEFT
INSPECTION COVERS) .
0.035 in (0.9 mm)
To remove and clean the spark plug:
WARNING
Before carrying out the following opera-
tions, let the engine and the exhaust
silencer cool down until they reach room
temperature, in order to avoid burns.
♦ Remove the spark plug cap (1).
♦ Using compressed air, blow all the dirt away
from the base of the spark plug.
Using the special spark plug wrench from
the tool kit, unscrew the spark plug.
Make sure that no dirt falls into the cylinder
through the spark plug hole.
♦
Inspect the spark plug, and insure that
there are no carbon deposits nor corrosion
marks on either electrode or the ceramic
nose that surrounds the center electrode.
If necessary, clean the spark plug with a
proprietary spark plug cleaner, and a
stainless steel brush.
♦ Using compressed air, carefully blow out
the spark plug after you have cleaned it.
Inspect for cracks on the insulating
material, electrode corrosion or erosion, or
deposits that you cannot remove. If the
spark plug shows any of these defects, it
must be replaced.
♦ Check the spark plug gap with a thickness
gauge.
♦ The gap must be 0.035 in (0.9 mm); if
necessary adjust it, carefully bending the
ground (outside) electrode.
♦
Make sure the gasket is in good condition.
With the gasket on, screw the spark plug
into the head by hand.
♦
Tighten the spark plug with the spark plug
wrench, approximately one-half turn after
it first snugly contacts the cylinder head.
Spark plug tightening torque:
14.47 ftlb (20 Nm).
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. 89 (TECHNICAL DATA),
in order not to compromise the life
and performance of the engine.
♦
Position the spark plug cap (1) properly,
so that it does not come off due to the
vibrations of the engine.
♦ Replace the left inspection cover, see p.
71 (REMOVING THE RIGHT AND LEFT
INSPECTION COVERS).
use and maintenance SR 50 75