Yamaha TZ125M1 Owner's Service Manual page 245

1st gear
Factory installed
Supplying part
2nd gear
Supplying part
Factory installed
Supplying part
Gear ratio
30/15 (2.000)
29/15 (1.933)
Gear ratio
35/21 (1.667)
31/19 (1.632)
27/17 (1.588)
7-11
SETTING
2. Loosen the stand installation bolt 1, then
rotate the dial gauge stand and set it close
to the center of the piston. Tighten the stand
installation bolt again.
NOTE:
Do not loosen the dial gauge installation bolt 2
while doing the above.
3. Set the piston at top dead center (TDC),
then measure the piston protrusion.
NOTE:
For measurement, avoid the top center pro-
jected area a on the piston head but measure
several positions above the piston pin as close
to the center as possible. The average of these
measurements indicates the piston protrusion.
EC71N001
Selection of transmission gear ratio
The following gear sets are contained in the
packing (or optional) to allow the rider to
change the gear ratios according to the circuit
condition or rider's preference.
C C CAUTION:
Select the transmission gears so that the
number of grooves in the wheel gear match
that of the pinion gear as shown below.
Trouble may be occurred if the selection is
different than that listed below.
a Groove
Part number
4JT-17211-00/4JT-17411-00
4JT-17211-10/4JT-17411-00
Part number
4JT-17221-00/4JT-17121-00
4JT-17221-30/4JT-17121-30
4JT-17221-10/4JT-17121-10
TUN
Number of
groove
–
1/–
Number of
groove
–
–
1