Spark Plugs - APRILIA RS 250 - 1998 Manual

SPARK PLUGS

Carefully read p. 47 (MAINTENANCE).
Check the spark plugs every 6000 km
(3700 mi).
Periodically remove the spark plugs and
clean them carefully, removing carbon de-
posits; change them if necessary.
To reach the spark plugs:
Remove the fuel tank, see p. 59 (REMO-
VING THE FUEL TANK).
To remove and clean the spark plugs:
Remove the cap (1) of the spark plug (2)
from the rear cylinder and the cap (3) of
the spark plug (4) from the front cylinder.
c
The description of the following
operations refers to one spark
plug only, but it is valid for both.
68 use and maintenance RS 250
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 0.7 ¸ 0.8 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.
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 kgm).
a
The spark plug must be well
tightened, otherwise the engine
may overheat and be seriously
damaged. Use the recommended type
of spark plug only, in order not to com-
promise the life and performance of the
engine.
RECOMMENDED SPARK PLUGS:
NGK NOTES
BR8 ECM If the standard spark plugs
tend to blacken, replace
them with these, having
lower heat rating.
BR9 ECM Standard spark plugs.
BR10 ECM If the standard spark plugs
tend to overheat and are
white, replace them with
these, having higher heat
rating.
Position the spark plug cap (1 and 3)
properly, so that it does not come off due
to the vibrations of the engine.
Put back the fuel tank.