Cleaning And Replacing The Spark Plugs - Ducati ST4s 2001 Manuel De L'utilisateur

Cleaning and replacing the spark plugs (fig. 48)
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 l.h. fairing, remove the spark plug caps 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
your 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 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.
0,6 ÷ 0,7 mm
E
fig. 48
63