Spark Plug - APRILIA AREA 51 - 1998 Manual

63$5. 3/8*
Carefully read p. 35 (MAINTENANCE).

Remember: 1 mile = 1.6 km
1 km = 0.625 miles
Check the spark plug after the first 500 km
and successively every 4000 km; change it
every 8000 km.
Periodically remove the spark plug and
clean it carefully, removing carbon depos-
its; change it if necessary.
To reach the spark plug:
Remove the right inspection cover, see
p. 46 (REMOVING THE RIGHT AND
LEFT INSPECTION COVERS).
48 use and maintenance Area 51
To remove and clean the spark plug:
Take off the spark plug cap (1).
Remove all the dirt from the base of the
spark plug, then unscrew it with the
spanner you will find in the tool kit and
extract it from its seat, taking care that
neither dust nor other substances enter
the cylinder.
Make sure that there are neither carbon
deposits, nor corrosion marks on the
electrode 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.
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 in-
sulating material, corroded electrodes or
excessive deposits, it must be changed.
Check the spark plug gap with a thick-
ness gauge.
The gap must be 0.5 0.6 mm; if neces-
sary adjust it, carefully bending the earth
electrode.
Make sure that the washer is in good
conditions. With the washer on, screw
the spark plug by hand in order not to
damage the thread.
Using the spanner provided in the tool
kit, tighten the spark plug, giving it half a
turn to compress the washer.

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. 60 (TECHNICAL DA-
TA), in order not to compromise the life
and performance of the engine.
Position the spark plug cap (1).
Put back the inspection cover.