Spark Plug Inspection - Yamaha TDR125 Owner's Manual

1. Spark plug wrench

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 condi-
tion of the engine. The ideal color on
the white insulator around the center
electrode is a medium-to-light tan
color for a motorcycle that is being
ridden normally. Do not attempt to
diagnose any problems
Instead, take the motorcycle to a
Yamaha dealer. The spark plug
should be periodically removed and
inspected because heat and deposits
PERIODIC MAINTENANCE AND MINOR REPAIR
1
1
1. Spark plug gap
EAU01651
will cause the spark plug to slowly
break down and erode. If electrode
erosion becomes excessive, or if car-
bon and other deposits are exces-
sive, the spark plug should be
replaced with the specified plug.
Specified spark plug:
BR9ES (NGK)
Before installing the spark plug, mea-
sure the electrode gap with a wire
thickness gauge and adjust it to
yourself.
specification.
Spark plug gap:
0.7 ~ 0.8 mm
When installing the plug, the gasket
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 speci-
fied torque as soon as possible.
6-8
Tightening torque:
Spark plug:
20 Nm (2.0 m0kg)
1
2
3
4
5
6
7
8
9