Yamaha TZ125M1 Owner's Service Manual page 238

SETTING
Run a few laps of the circuit to check the
engine for response to revolutions.
On the other hand, if the use of a different
jet needle appears to produce less power,
change to a jet needle of a smaller size.
w
Example:N8VW ≥ N8VH
Factory-set jet needle
NOTE:
• Refer to "Jet needle" (P7-5) about the jet
needle specification.
• Difference between individual riders or differ-
ence between circuit layouts greatly affect the
jet needle setting.
1. Rider who frequently uses mid-open throt-
tle
2. Circuit that requires frequent throttle open-
ing and closing
3. Wet environment
Conditions as mentioned above require a
longer period of throttle closing, resulting in
the drawn in mixture staying longer in the
crankcase. Such setting in turn will inevitably
cause the mixture to be richer at the next
throttle opening, a jet needle of a larger size
has to be used.
Example of jet needle setting
The above settings are an example of the
results obtained on our test course, and are
just for reference.
7-4
TUN
N8VH