Yamaha YZ125X 2023, Owner'S Manual

Page: 127 / 146

ENGINE
8-2
EAM30593
EFFECTS OF THE SETTING PARTS ON THE
THROTTLE VALVE OPENING
EAM30594
MAIN JET ADJUSTMENT
The richness of air-fuel mixture with 3/4–4/4
throttle can be set by changing the main jet “1”.
* For AUS/NZL
1. Spark plug is too hot.
Select a main jet having higher calibrating
No. than standard. (To be enriched)
2. Spark plug is wet.
Select a main jet having lower calibrating No.
than standard. (To be leaned out)
EAM30595
PILOT AIR SCREW ADJUSTMENT
The richness of the air-fuel mixture with the
throttle fully closed to 1/8 open can be set by
turning the pilot air screw “1”.
Turning in the pilot air screw will make the mix-
ture enrich at low speeds, and turning it out will
lean it.
* For AUS/NZL
EAM30596
PILOT JET ADJUSTMENT
The richness of air-fuel mixture with the throttle
fully closed to 1/2 open can be set by turning the
pilot jet “1”. It is changed when adjustment can-
not be made by the pilot air screw alone.
A larger size jet results in a richer mixture at low
speeds, and a smaller size in a leaner mixture.
*For AUS/NZL
A. Closed
B. Full-open
1. Pilot air screw
2. Pilot jet
3. Jet needle
4. Diameter of straight portion
5. Clip position
6. Throttle valve
7. Main jet
Standard main jet
#160
*#162
Standard pilot air
screw position
1-1/2 turns out
*2 turns out
Standard pilot jet
#65
*#60