Electrical; Spark Plug Inspection - Yamaha TTR90(M) Owner's Service Manual

ELECTRICAL/SPARK PLUG INSPECTION
EC370000

ELECTRICAL

EC371001

SPARK PLUG INSPECTION

1. Remove:
Spark plug
2. Inspect:
Electrode 1
Wear/damage
Insulator color 2
Normal condition is a medium to light
tan color.
Distinctly different color
engine condition.
NOTE:
When the engine runs for many hours at low
speeds, the spark plug insulator will become
sooty, even if the engine and carburetor are in
good operating condition.
3. Measure:
Plug gap a
Use a wire gauge or thickness gauge.
Out of specification
Spark plug gap:
0.6 ~ 0.7 mm (0.02 ~ 0.03 in)
Standard spark plug:
CR6HSA (NGK)
U20FSR-U (DENSO)
4. Clean the plug with a spark plug cleaner
if necessary.
5. Tighten:
Spark plug
NOTE:
Before installing a spark plug, clean the gas-
ket surface and plug surface.
Finger-tighten a the spark plug before
torquing to specification b.
3 - 19
INSP
ADJ
Replace.
Check the
Regap.
13 Nm (1.3 m · kg, 9.4 ft · lb)