Road Condition And Examples Of Carburetor Setting; Examples Of Carburetor Setting Depending On Symptom - Yamaha YZ125X 2023 Owner's Manual

EAM30601

ROAD CONDITION AND EXAMPLES OF CARBURETOR SETTING

Under 10 C
(50 F)
(Winter)
A
Main jet
B
A NYDF-3
Jet needle
B NYDE-2
A
Pilot jet
B
A
Pilot air
screw
B
A. Except for AUS/NZL
B. For AUS/NZL
TIP
Optimum pilot air screw setting can be obtained by adding the ex-factory number of the same screw
back-out turns to any required value provided in the chart. For example, if the ex-factory number is "1",
add "1" to the value chosen in the chart.
EAM30602

EXAMPLES OF CARBURETOR SETTING DEPENDING ON SYMPTOM

Symptom
• At full throttle
Stall at high speeds
*Hard breathing
Shearing noise
Whitish spark plug

Lean mixture
• At full throttle
Speed pick-up stops
Slow speed pick-up
Slow response
Sooty spark plug

Rich mixture
General condition
15–25 C
(59–77 F)
(Spring,
Autumn)
#162 #160
#165 #162
NYCF-2
NYEE-2
#68 #65
#62 #60
0 0
0 0
Increase main jet calibration no.
(Gradually)
Decrease main jet calibration no.
(Gradually)
*In case of racing slight enrichment of
mixture reduces engine trouble.
Over 25 C Under 10 C
(77 F) (50 F)
(Summer) (Winter)
#158
#160
NYDF-2 NYCF-3
NYDE-1 NYEE-3
#62
#58
0
0
Setting
8-6
Sandy condition
15–25 C
(59–77 F)
(Spring,
Autumn)
#168 #165
#170 #168
NYDF-3
NYDE-2
#70 #68
#65 #62
0 0
0 0
Checking
• Discoloration of spark plug 
If tan color, it is in good condition.
• If cannot be corrected:
Clogged float valve seat
Clogged fuel hose
Clogged fuel cock
• Discoloration of spark plug 
If tan color, it is in good condition.
• If cannot be corrected:
Clogged air filter
Fuel overflow from carburetor
Clogged main air passage or
clogged filter
ENGINE
Over 25 C
(77 F)
(Summer)
#162
#165
NYCF-2
NYEE-2
#65
#60
0
0