diagram YAMAHA YZ250F 2016 Owner's Manual

CABLE ROUTING DIAGRAM
2-41

AC MAGNETO
5-60
2. Install:
• Woodruff key “1”
• Rotor “2”
TIP
• Clean the contact surfaces of the tapered por-
tions of the crankshaft and rotor.
• When installing the woodruff key, make sure
that its flat surface “a” is in parallel with the
crankshaft center line “b”.
• When installing the rotor, align the keyway “c”
of the rotor with the woodruff key.
3. Install:
• Washers
• Nut (rotor) “1”
4. Install:
• Dowel pin “1”
• Gasket (left crankcase cover) “2”
• Left crankcase cover “3”
• Lead holder “4”
• Bolt (left crankcase cover) “5”
TIP
Tighten the bolts in stages and in a crisscross
pattern.5. Connect:
• AC magneto lead
Refer to “CABLE ROUTING DIAGRAM” on
page 2-31.
Nut (rotor)
65 Nm (6.5 m·kgf, 47 ft·lbf)
Bolt (left crankcase cover)
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
b11
c
2 a
T R..
1
New
T R..
1
1
2
3
5
5
5
5
4
45

8
ELECTRICAL SYSTEM
IGNITION SYSTEM.......................................................................................... 8-2
CIRCUIT DIAGRAM ................................................................................... 8-2
TROUBLESHOOTING ............................................................................... 8-4
CHARGING SYSTEM....................................................................................... 8-6
CIRCUIT DIAGRAM ................................................................................... 8-6
TROUBLESHOOTING ............................................................................... 8-8
FUEL INJECTION SYSTEM........................................................................... 8-10
CIRCUIT DIAGRAM ................................................................................. 8-10
YAMAHA DIAGNOSTIC TOOL ................................................................ 8-12
TROUBLESHOOTING DETAILS ............................................................. 8-13
FUEL PUMP SYSTEM.................................................................................... 8-32
CIRCUIT DIAGRAM ................................................................................. 8-32
TROUBLESHOOTING ............................................................................. 8-34
ELECTRICAL COMPONENTS....................................................................... 8-36
CHECKING THE SWITCHES .................................................................. 8-38
CHECKING THE IGNITION SPARK GAP................................................ 8-41
CHECKING THE SPARK PLUG CAP ...................................................... 8-41
CHECKING THE IGNITION COIL ............................................................ 8-41
CHECKING THE CRANKSHAFT POSITION SENSOR........................... 8-42
CHECKING THE ECU .............................................................................. 8-43
CHECKING THE STATOR COIL ............................................................. 8-43
CHECKING THE RECTIFIER/REGULATOR ........................................... 8-43
CHECKING THE COOLANT TEMPERATURE SENSOR........................ 8-44
CHECKING THE THROTTLE POSITION SENSOR ................................ 8-44
CHECKING THE THROTTLE POSITION SENSOR INPUT VOLTAGE .. 8-45
CHECKING THE INTAKE AIR PRESSURE SENSOR ............................ 8-46
CHECKING THE INTAKE AIR TEMPERATURE SENSOR ..................... 8-46
CHECKING THE NEUTRAL SWITCH ..................................................... 8-46
CHECKING THE FUEL INJECTOR ......................................................... 8-47

IGNITION SYSTEM
8-2
EAS1SM9319
IGNITION SYSTEM
EAS1SM9320CIRCUIT DIAGRAM
ONOFF
R O
OR
RRRRRRR
BBBBB
LLLB/LB/LB/LB/LB/LB/L
B/L
Gy
W
W
W
W
R
R
B
B
B
Y/B
Y/B
Y/W
Y/WB/YL/WB/R
B/Y
B/Y
B/W
R/B
R/B
B/R
B/R
G/WP/B
P/B
B/L
B/L
B/L
G/W
Br/W
Br/W
B/LB/L
B/W
SbP
Sb
Sb
P
P
P
L
L
LY
Y
B
B
LgGy
Lg
R
R
R
R
R
R
R
O
O
O
O
WWW W
W W
W WR B
B/LGyB Gy
BRRB
RLgB/W
B R
B/YB
B B
PY/BSbSbY/WP
BGy R
B/WB/LLYP/BG/WB/R
R/BLg
Br/W
P
O
B/YY/BSb
RR/B
RB/R
B/LBr/WB/L G/W
LYB/L
B/LP/BL
LLLRRRRRRR
BBB BB
B/L B/L B/L B/L B/L B/L

IGNITION SYSTEM
8-5
8. Check the ignition system wire har-
ness.
Refer to “CIRCUIT DIAGRAM” on
page 8-2.NG 
Repair or replace the wire harness.
OK 
Replace the ECU.

CHARGING SYSTEM
8-6
EAS27200
CHARGING SYSTEM
EAS1SM9322CIRCUIT DIAGRAM
ONOFF
R O
OR
RRRRRRR
BBBBB
LLLB/LB/LB/LB/LB/LB/L
B/L
Gy
W
W
W
W
R
R
B
B
B
Y/B
Y/B
Y/W
Y/WB/YL/WB/R
B/Y
B/Y
B/W
R/B
R/B
B/R
B/R
G/WP/B
P/B
B/L
B/L
B/L
G/W
Br/W
Br/W
B/LB/L
B/W
SbP
Sb
Sb
P
P
P
L
L
LY
Y
B
B
LgGy
Lg
R
R
R
R
R
R
R
O
O
O
O
WWW W
W W
W WR B
B/LGyB Gy
BRRB
RLgB/W
B R
B/YB
B B
PY/BSbSbY/WP
BGy R
B/WB/LLYP/BG/WB/R
R/BLg
Br/W
P
O
B/YY/BSb
RR/B
RB/R
B/LBr/WB/L G/W
LYB/L
B/LP/BL
LLLRRRRRRR
BBB BB
B/L B/L B/L B/L B/L B/L

CHARGING SYSTEM
8-8
EAS1SM9323TROUBLESHOOTING
The condenser is not being charged.
TIP
Before troubleshooting, remove the following part (s):
1. Seat
2. Air scoop (left)
1. Check the entire charging system’s
wiring.NG 
Reconnect.
OK 
2. Check the rectifier/regulator.
Refer to “CHECKING THE RECTI-
FIER/REGULATOR” on page 8-43.NG 
Replace the rectifier/regulator.
OK 
3. Check the stator coil.
Refer to “CHECKING THE STA-
TOR COIL” on page 8-43.NG 
Replace the stator coil.
OK 
4. Check the charging system wire
harness.
Refer to “CIRCUIT DIAGRAM” on
page 8-6.NG 
Repair or replace the wire harness.
OK 
Replace the condenser.

FUEL INJECTION SYSTEM
8-10
EAS1SM9324
FUEL INJECTION SYSTEM
EAS1SM9325CIRCUIT DIAGRAM
ONOFF
R O
OR
RRRRRRR
BBBBB
LLLB/LB/LB/LB/LB/LB/L
B/L
Gy
W
W
W
W
R
R
B
B
B
Y/B
Y/B
Y/W
Y/WB/YL/WB/R
B/Y
B/Y
B/W
R/B
R/B
B/R
B/R
G/WP/B
P/B
B/L
B/L
B/L
G/W
Br/W
Br/W
B/LB/L
B/W
SbP
Sb
Sb
P
P
P
L
L
LY
Y
B
B
LgGy
Lg
R
R
R
R
R
R
R
O
O
O
O
WWW W
W W
W WR B
B/LGyB Gy
BRRB
RLgB/W
B R
B/YB
B B
PY/BSbSbY/WP
BGy R
B/WB/LLYP/BG/WB/R
R/BLg
Br/W
P
O
B/YY/BSb
RR/B
RB/R
B/LBr/WB/L G/W
LYB/L
B/LP/BL
LLLRRRRRRR
BBB BB
B/L B/L B/L B/L B/L B/L

FUEL PUMP SYSTEM
8-32
EAS1SM9328
FUEL PUMP SYSTEM
EAS1SM9329CIRCUIT DIAGRAM
ONOFF
R O
OR
RRRRRRR
BBBBB
LLLB/LB/LB/LB/LB/LB/L
B/L
Gy
W
W
W
W
R
R
B
B
B
Y/B
Y/B
Y/W
Y/WB/YL/WB/R
B/Y
B/Y
B/W
R/B
R/B
B/R
B/R
G/WP/B
P/B
B/L
B/L
B/L
G/W
Br/W
Br/W
B/LB/L
B/W
SbP
Sb
Sb
P
P
P
L
L
LY
Y
B
B
LgGy
Lg
R
R
R
R
R
R
R
O
O
O
O
WWW W
W W
W WR B
B/LGyB Gy
BRRB
RLgB/W
B R
B/YB
B B
PY/BSbSbY/WP
BGy R
B/WB/LLYP/BG/WB/R
R/BLg
Br/W
P
O
B/YY/BSb
RR/B
RB/R
B/LBr/WB/L G/W
LYB/L
B/LP/BL
LLLRRRRRRR
BBB BB
B/L B/L B/L B/L B/L B/L

FUEL PUMP SYSTEM
8-34
EAS1SM9330TROUBLESHOOTING
The fuel pump fails to operate.
TIP
Before troubleshooting, remove the following part(s):
1. Seat
2. Side cover (left/right)
3. Air scoop (left/right)
4. Fuel tank
5. Air filter case cover
1. Check the fuel pump system wire
harness connections.NG 
Reconnect.
OK 
2. Check the engine stop switch.
Refer to “CHECKING THE
SWITCHES” on page 8-38.NG 
Replace the engine stop switch.
OK 
3. Check fuel pressure.
Refer to “CHECKING THE FUEL
PRESSURE” on page 7-3.NG 
Replace the fuel pump.
OK 
4. Check the fuel pump system wire
harness.
Refer to “CIRCUIT DIAGRAM” on
page 8-32.NG 
Repair or replace the wire harness.
OK 
Replace the ECU.