Spark Plug Inspection - Yamaha Wild Star XV1600A Owner's Manual

a. Spark plug gap

Spark plug inspection

The spark plug is an important engine
component and should be inspected
periodically, preferably by a Yamaha
dealer. The condition of the spark plug
can indicate the condition of the en-
gine.
Normally, all spark plugs from the
same engine should have the same
color on the white insulator around the
center electrode. The ideal color at this
point is a medium-to-light tan color for a
motorcycle that is being ridden normal-
ly. If one spark plug shows a distinctly
different color, there could be some-
thing wrong with the engine.
PERIODIC MAINTENANCE AND MINOR REPAIR
Do not attempt to diagnose such prob-
lems yourself. Instead, take the motor-
cycle to a Yamaha dealer. The spark
plugs should be periodically removed
and inspected because heat and de-
posits will cause any spark plug to
slowly break down and erode. If elec-
trode erosion becomes excessive, or if
carbon and other deposits are exces-
sive, the spark plug should be replaced
EAU01639
with the specified plug.
Specified spark plug:
DPR7EA-9/NGK or
X22EPR-U9/DENSO
Before installing any spark plug, mea-
sure the electrode gap with a wire
thickness gauge and adjust it to specifi-
cation.
Spark plug gap:
0.8 ~ 0.9 mm
When installing a spark plug, the gas-
ket surface should always be cleaned
and a new gasket used. Any grime
should be wiped off from the threads
and the spark plug tightened to the
specified torque.
NOTE:
@
If a torque wrench is not available when
installing a spark plug, a good estimate
of the correct torque is 1/4 to 1/2 turn
past finger tight. The spark plug should
be tightened to the specified torque as
soon as possible.
@
6-6
Tightening torque:
Spark plug:
17.5 Nm (1.75 m·kg)
6