Cleaning and replacing the spark plugs (fig. 65)
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
Remove the LH fairing, remove the spark plug caps and
spark plugs from the cylinder head using the wrench
supplied with the bike.
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 vitrified appearance, change the spark plug.
Check electrode gap: it should be 0.6-0.7 mm.
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 misfiring 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. Tighten until thread is
fully 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.
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