Yamaha TZ125M1 Owner's Service Manual page 239

SETTING
4. Adjustment of jet needle clip position
Mid-open adjustment for the jet needle clip
position 1 follows the completion of the
adjustment of the jet needle. If the mixture
is too rich or too lean in the mid-open posi-
tion, irregular engine operation and poor
acceleration will result. Whether or not the
richness of the mixture is proper is hard to
be determined by means of the spark plug
and therefore, it should be judged from your
feeling of actual engine operation.
• Too rich in the mid-open position (Rough
engine operation is felt and the engine will
not pick up speed smoothly)
Step up the jet needle clip by one groove
and move down the needle to lean out the
mixture.
• Too lean in the mid-open position (The
engine breathes hard and will not pick up
speed quickly)
w
Step up the jet needle clip by one groove
and move up the needle to enrich the mix-
ture.
Factory-set clip position
EC71S000
Jet needle
On the carburetors used in the TZ125, the
main nozzle is press-fitted, so it can not be
replaced. Therefore,
requires the change of the jet needle.
The jet needle setting parts, having the same
taper angle, are available in different straight
portion diameters and in different taper starting
positions.
Example:
N8VH-3
Clip position
Diameter a of straight portion
d Jet needle number
NOTE:
Changing from N8VH to N8WH has the same
effect as raising the clip position by half.
Example:
The 3rd position of N8WH corresponds to the
2.5th position of N8VH.
7-5
TUN
No.3 Groove
carburetor setting