Cleaning And Renewing The Spark Plugs - Ducati MONSTER S4R S Use And Maintenance Manual

Cleaning and renewing the spark plugs

(fig. 65)
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 Service Centre.
Also check the central electrode; if it is worn or glazed,
renew the spark plug.
Check the electrode gap, which must be:
0,6÷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 socket on the head and take care not to
allow foreign bodies to fall into 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, after tightening by hand,
turn the unit a further half turn with the provided wrench.
Important
Do not use spark plugs with an unsuitable heat rating
or incorrect reach.
The spark plug must be tightened correctly.
E
fig. 65
65