Yamaha TZ125M1 Owner's Service Manual page 243

SETTING
EC71J001
Plug chop
When checking the discoloration of the spark
plug and piston head, push the "ENGINE
STOP" button while running along a straight
lane at full throttle, disengage the clutch at the
same time and stop the engine. Then let your
machine go back to the pit by inertia. This is
called a "plug chop".
C C CAUTION:
• When you do a "plug chop", pay attention
to your surrounding environment to avoid
interference with other riders.
• Do not shift down while riding your
machine by inertia (as it may cause a
seizure of the clutch push rod and ball).
EC71K003
Setting of cylinder gasket
The use of the supplied gaskets of different
thicknesses makes it possible to change the
combustion chamber volume to deal with
changing weather conditions.
Not much torque is felt with slow engine accel-
eration ≥ Reduce the combustion chamber
volume.
Torque is felt with no higher revolutions ≥
Expand the combustion chamber volume.
Actual combustion
Thickness
chamber volume
0.8 mm Approx. 9.42 cm
(0.031 in) (0.332 lmp oz, 0.318 US oz)
0.7 mm Approx. 9.19 cm
(0.028 in) (0.323 lmp oz, 0.311 US oz) Supplying
0.6 mm Approx. 8.96 cm
(0.024 in) (0.315 lmp oz, 0.303 US oz)
NOTE:
• Finish adjusting the carburetor setting before
changing the gasket.
• A change of 0.1 mm (0.004 in) for the gasket
causes a change of approximately 0.23 cm
(0.0081 lmp oz, 0.0078 US oz) of the com-
bustion chamber volume.
7-9
TUN
Type
3
STD
3
3 parts
3