Cleaning And Renewing The Spark Plugs - Ducati Monster S4RS Owner's Manual

Cleaning and renewing the spark plugs (fig. 61)
Spark plugs are an important part of the engine and should
be checked at regular intervals.
This is a relatively simple operation and provides a good
indication of how well the engine is running.
Disconnect the HT leads from the spark plugs and remove
them from the cylinder heads with the wrench provided.
Check the colour of the ceramic insulation around the
central electrode: an even brown colour is a sign that the
engine is in good condition.
If the insulation is any other colour, or if there are dark
deposits, renew the spark plug and describe the condition
of the old plug to a Ducati dealer or authorized workshop.
Also check the central electrode; if it is worn or glazed,
renew the spark plug.
Check the electrode gap, which must be:
0.6 to 0.7 mm.
Important
Take care when bending the side electrode to adjust
the gap. A gap outside the specified limits will adversely
affect engine performance and may lead to difficult
starting or erratic idling.
Thoroughly clean the electrode and insulation using a wire
brush, and check the condition of the washer.
Clean the spark plug seat in the cylinder head, and take care
not to allow foreign objects to fall inside the combustion
chamber.
Insert the spark plug in the cylinder head and screw in fully
by hand. Tighten to a torque of 20 Nm.
If you do not have a torque wrench available, first tighten
the spark plugs by hand and then use the spark plug
wrench provided to tighten them a further half turn.
Important
Do not use spark plugs with an unsuitable heat rating
or incorrect reach.
The spark plug must be tightened correctly.
E
fig. 61
61