Cleaning And Replacing The Spark Plugs - Ducati Monster 400 Owner's Manual

Cleaning and replacing the spark plugs

E
(fig. 55)
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 caps and remove the spark plugs
from the head using the suitable supplied wrench.
Check the colour of the insulating ceramic material of the
central electrode: a light brown, even colour is a sign of good
engine condition.
If colour has altered or you find any dark deposits, change the
spark plug and report this to your Dealer or authorised
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
0.7 - 0.8 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 erratic 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.
58
Refit spark plug into cylinder head. Snug it finger-tight until it
is fully seated into the head. Tighten the spark plug to 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.
Important
Never use spark plugs with a heat rating other than
recommended or a thread length other than standard.
Spark plugs should be tightened properly.
0,7÷0,8 mm
fig. 55