Ducati MONSTER S4, Owner'S Manual

Page: 114 / 273

Cleaning and replacing the spark plugs (fig. 42)
Spark plugs are essential to smooth engine running and
should be checked at regular intervals.
This is done quite easily and quickly and provides a good
measure of engine condition.
Remove the spark plug coils from the cylinder head using
the wrench supplied with the bike.
Check the color of the insulating ceramic material of the
central electrode: a light brown, even color is a sign of
good engine condition. If color has altered or you find any
dark deposits, change the spark plug and report this to a
Ducati dealer or authorized workshop.
Check wear on the central electrode. If it looks worn out
or has a vitreous appearance, change the spark plug.
Check electrode gap: it should be 0.6-0.7 mm.
Important
If the gap needs adjusting, be very careful when
bending the side electrode. If gap is too wide or too
close, engine performance will be affected. This could
also cause difficult starting or irregular idling.
Clean the electrode and the insulating material accurately
using a small metal brush and check seal condition.
Clean the seat in the cylinder head. Be careful not to let
any foreign matters fall into the combustion chamber.
Refit spark plug into cylinder head. Snug it finger-tight
until it is fully seated into the head. Tighten the spark plug
at 20 Nm. If you do not have a torque wrench, you can
use the wrench supplied with the tool kit to tighten the
spark plug an additional 1/2 turn.
50
E
–10
Unigrade
Multigrade
0 10 20 30 40
°
C
40
20W–40 20W–50
15W–40 15W–50
10W–40
10W–30
10W
20W
20
30
Viscosity
SAE 10W-40
The other viscosity degrees indicated in the table can be
used if the local average temperature is within the limits
specified for that oil viscosity.
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