Checking The Spark Plug - Yamaha DT125R Owner's Manual

Panels D and E
1
1. Screw
To remove one of the panels
Remove the screw, and then pull the
panel off as shown.
To install the panel
Place the panel in the original posi-
tion, and then install the screw.
PERIODIC MAINTENANCE AND MINOR REPAIR
EAU19292

Checking the spark plug

1
1. Spark plug inspection
The spark plug is an important engine
component, which should be chec-
ked periodically, preferably by a
Yamaha dealer. Since heat and depo-
sits will cause any spark plug to
slowly erode, it should be removed
and checked in accordance with the
periodic maintenance and lubrication
chart. In addition, the condition of the
spark plug can reveal the condition of
the engine.
EAU19620 The porcelain insulator around the
center electrode of the spark plug
should be a medium-to-light tan (the
ideal color when the vehicle is ridden
normally). If the spark plug shows a
distinctly different color, the engine
could be defective. Do not attempt to
diagnose such problems yourself.
Instead, have a Yamaha dealer check
the vehicle.
If the spark plug shows signs of elec-
trode erosion and excessive carbon
or other deposits, it should be repla-
ced.
Before installing a spark plug, the
spark plug gap should be measured
with a wire thickness gauge and, if
necessary, adjusted to specification.
Clean the surface of the spark plug
gasket and its mating surface, and
then wipe off any grime from the
spark plug threads.
6-6
Specified spark plug:
BR8ES (NGK)
Spark plug gap:
0,7-0,8 mm (0,0276-0,0315 in)
6