cooling YAMAHA WR 250F 2015 User Guide

7
COOLING SYSTEM
RADIATOR....................................................................................................... 7-1
HANDLING NOTE ...................................................................................... 7-3
CHECKING THE RADIATOR ..................................................................... 7-3
WATER PUMP.................................................................................................. 7-4
REMOVING THE OIL SEAL ....................................................................... 7-6
CHECKING THE WATER PUMP ............................................................... 7-6
CHECKING THE BEARING....................................................................... 7-6
INSTALLING THE OIL SEAL..................................................................... 7-6
ASSEMBLING THE WATER PUMP........................................................... 7-6

9
ELECTRICAL SYSTEM
IGNITION SYSTEM.......................................................................................... 9-2
CIRCUIT DIAGRAM ................................................................................... 9-2
TROUBLESHOOTING ............................................................................... 9-4
ELECTRIC STARTING SYSTEM..................................................................... 9-6
CIRCUIT DIAGRAM ................................................................................... 9-6
STARTING CIRCUIT CUT-OFF SYSTEM OPERATION ........................... 9-8
TROUBLESHOOTING ............................................................................. 9-10
CHARGING SYSTEM..................................................................................... 9-12
CIRCUIT DIAGRAM ................................................................................. 9-12
TROUBLESHOOTING ............................................................................. 9-14
LIGHTING SYSTEM....................................................................................... 9-16
CIRCUIT DIAGRAM ................................................................................. 9-16
TROUBLESHOOTING ............................................................................. 9-18
SIGNALING SYSTEM.................................................................................... 9-20
CIRCUIT DIAGRAM ................................................................................. 9-20
TROUBLESHOOTING ............................................................................. 9-22
COOLING SYSTEM........................................................................................ 9-24
CIRCUIT DIAGRAM ................................................................................. 9-24
TROUBLESHOOTING ............................................................................. 9-26
FUEL INJECTION SYSTEM........................................................................... 9-28
CIRCUIT DIAGRAM ................................................................................. 9-28
ECU SELF-DIAGNOSTIC FUNCTION ..................................................... 9-30
TROUBLESHOOTING METHOD ............................................................. 9-31
YAMAHA DIAGNOSTIC TOOL ................................................................ 9-32
TROUBLESHOOTING DETAILS ............................................................. 9-35
FUEL PUMP SYSTEM.................................................................................... 9-56
CIRCUIT DIAGRAM ................................................................................. 9-56
TROUBLESHOOTING ............................................................................. 9-58

COOLING SYSTEM
9-24
EAS2GB2371
COOLING SYSTEM
EAS2GB2372CIRCUIT DIAGRAM
ONOFF
ONOFF
B
AA
BBB
BBB
RRR
RRR/L
Br Br Br
Br Br
WWW(Gy)
(Gy)B/LGyWW WB Gy
B R
W W WWW W
BR
R,R/Y
G
R
Y/B
R,R/W
Br
RL/R
(B)R/YR/WBr/WL/G
Br/W,BrL/W
(B) (B)Br BrL/Y Y/R
G/YBrBBBrBrL/YY/W
(B)(B)BB GG/Y
RR/L
R Lg
W/B
(B) B
GyBrRW/BB/LLYPG/WB/Y
R/BLgG/YW
Br/W
OL/RY/BB/OL/BSbY/R L/Y P/L
Y/G
(Gy)R/L R/BR/LB/Y
R/WR/L
R/W,BrP/L
R/L R/L
(B)
(B)
(B)
(L)
(L)(B) BR/LLBR/L R/L R/L R/L R/L B/L B/L B/L B/L B/L B/L B/LLLLLBBBB
Br Br Br Br
B/LBr/W
B/LG/WLYB/L
B/LPLB/LY/GL
(B)
(B)B/OBB BSbW/B
Sb
SbG/B
L/G,L/WL/BBrG/BG/BB
BB
(B)
(B)L/BBB B
Br Br
Br BrBr
BB LY
(B)
(B)
(B)
(B) GB
Ch Dg
Y BBr R
B W
B/WR W
Ch DgYBBrR/WBW
(B)BRW
BBBBBB
RRRRRR/L
BrBrBrBrBr
Br
Br
BrBrBrBrR/LR/LR/LR/LR/L
B
LLLP
PL
Y
Y
RR
Br
R/LR/L
R/L
P/L
P/L
R/L
R/L
R/L
R/B
R/B
L/RL/Y
L/Y
Y/R
Y/R
G/Y
G/YG/Y
G/Y
B/Y
B/Y
R/LB/LB/L
B/LB/LB/LY/G
Y/GB/L
B/OL/BY/BW/B
G/B
L/B
W/BW/B
L/BL/BL/GL/W
L/W
L/R
Br/W
Br/W
R/W
R/W
R/Y
R/Y
G/BG/B
G/B
B/O
B/LB/LB/LB/LB/LB/LB/L
G/W
G/W
Br/W
Br/W
R/WR/WBr
OOO
O
R
RGy
R
LLLLBBBB
B
B
B
B
BB
B
RRWW
YDgCh
RW
BrBrBrBr
Br
B
W
Sb
SbSb
SbBr
Br
B
Br
Lg
Lg
R/L
R
R
RR
Gy
B
WWWWWW
R
RRGGBB
B
Y/B
RB
BB
BBBBB
Br
Br
Br
B
B
L/G
B/L
B/WB/W
W/B
BDgYCh

COOLING SYSTEM
9-25
1. Joint connector
2. Joint connector
3. Joint connector
7. Main relay
9. Battery
10.Frame ground
11.Starter relay
12.Main fuse
22.ECU (engine control unit)
27.Radiator fan motor relay
28.Radiator fan motor fuse
29.Radiator fan motor
30.Joint connector
32.Coolant temperature sensor
48.Frame ground

COOLING SYSTEM
9-26
EAS2GB2373TROUBLESHOOTING
The radiator fan motor fails to turn.
TIP
Before troubleshooting, remove the following part(s):
1. Seat
2. Side cover (left)
3. Air scoop (left/right)
4. Fuel tank
1. Check the fuse.
Refer to “CHECKING THE FUSES”
on page 9-68.NG 
Replace the fuse(s).
OK 
2. Check the battery.
Refer to “CHECKING AND
CHARGING THE BATTERY” on
page 9-69.NG 
• Clean the battery terminals.
• Recharge or replace the battery.
OK 
3. Check the main relay.
Refer to “CHECKING THE RE-
LAYS” on page 9-72.NG 
Replace the main relay.
OK 
4. Check the radiator fan motor.
Refer to “CHECKING THE RADIA-
TOR FAN MOTOR” on page 9-78.NG 
Replace the radiator fan motor.
OK 
5. Check the radiator fan motor relay.
Refer to “CHECKING THE RE-
LAYS” on page 9-72.NG 
Replace the radiator fan motor relay.
OK 
6. Check the coolant temperature sen-
sor.
Refer to “CHECKING THE COOL-
ANT TEMPERATURE SENSOR”
on page 9-78.NG 
Replace the coolant temperature sensor.
OK 
7. Check the entire cooling system’s
wiring.
Refer to “CIRCUIT DIAGRAM” on
page 9-16.NG 
Properly connect or repair the cooling sys-
tem’s wiring.
OK 
Replace the ECU.

COOLING SYSTEM
9-27
EAS2GB2374

10
TROUBLESHOOTING
TROUBLESHOOTING.................................................................................... 10-1
GENERAL INFORMATION ...................................................................... 10-1
STARTING FAILURES ............................................................................. 10-1
INCORRECT ENGINE IDLING SPEED ................................................... 10-1
POOR MEDIUM-AND-HIGH-SPEED PERFORMANCE .......................... 10-2
SHIFTING IS DIFFICULT ......................................................................... 10-2
SHIFT PEDAL DOES NOT MOVE ........................................................... 10-2
JUMPS OUT OF GEAR............................................................................ 10-2
CLUTCH SLIPS ........................................................................................ 10-2
CLUTCH DRAGS ..................................................................................... 10-2
OVERHEATING ....................................................................................... 10-2
OVERCOOLING ....................................................................................... 10-3
POOR BRAKING PERFORMANCE ......................................................... 10-3
FRONT FORK OIL LEAKING ................................................................... 10-3
FAULTY FRONT FORK LEGS ................................................................. 10-3
UNSTABLE HANDLING ........................................................................... 10-3
HEADLIGHT DOES NOT COME ON ....................................................... 10-4
HEADLIGHT BULB BURNT OUT............................................................. 10-4
TAILLIGHT DOES NOT COME ON ......................................................... 10-4
LIST OF SELF-DIAGNOSTIC AND FAIL-SAFE ACTIONS........................... 10-5

TROUBLESHOOTING
10-2
EAS2GB2411POOR MEDIUM-AND-HIGH-SPEED PER-
FORMANCE
Refer to “STARTING FAILURES” on page 10-
1.
Engine
1. Air filter
• Clogged air filter element
Fuel system
1. Fuel pump
• Faulty fuel pump
2. Throttle body
• Defective throttle body
3. ECU
• Faulty ECU
EAS2GB2412SHIFTING IS DIFFICULT
Refer to “CLUTCH” on page 6-40.
EAS2GB2413SHIFT PEDAL DOES NOT MOVE
Engine
1. Shift shaft
• Bent shift shaft
2. Shift drum and shift forks
• Foreign object in a shift drum groove
• Seized shift fork
• Bent shift fork guide bar
3. Transmission
• Seized transmission gear
• Foreign object between transmission gears
• Improperly assembled transmission
EAS2GB2414JUMPS OUT OF GEAR
Engine
1. Shift shaft
• Incorrect shift pedal position
• Improperly returned stopper lever
2. Shift forks
• Worn shift fork
3. Shift drum
• Incorrect axial play
• Worn shift drum groove
4. Transmission
• Worn gear dog
EAS2GB2415CLUTCH SLIPS
Engine
1. Clutch
• Improperly assembled clutch
• Loose or fatigued clutch spring
• Worn friction plate
• Worn clutch plate
2. Engine oil
• Incorrect oil level
• Incorrect oil viscosity (low)
• Deteriorated oil
EAS2GB2416CLUTCH DRAGS
Engine
1. Clutch
• Unevenly tensioned clutch springs
• Warped pressure plate
• Bent clutch plate
• Swollen friction plate
• Bent clutch push rod
• Damaged clutch boss
• Burnt primary driven gear bushing
2. Engine oil
• Incorrect oil level
• Incorrect oil viscosity (high)
• Deteriorated oil
EAS2GB2417OVERHEATING
Engine
1. Cylinder head and piston
• Heavy carbon buildup
• Clogged coolant passages
2. Engine oil
• Incorrect oil level
• Incorrect oil viscosity
• Inferior oil quality
Cooling system
1. Coolant
• Low coolant level
2. Radiator
• Damaged or leaking radiator
• Faulty radiator cap
• Bent or damaged radiator fin
3. Water pump
• Damaged or faulty water pump
• Damaged hose
• Improperly connected hose
• Damaged pipe
• Improperly connected pipe

TROUBLESHOOTING
10-3
Fuel system
1. Throttle body
• Damaged or loose throttle body joint
2. Air filter
• Clogged air filter element
Chassis
1. Brake(s)
• Dragging brake
Electrical system
1. Spark plug
• Incorrect spark plug gap
• Incorrect spark plug heat range
2. Ignition system
• Faulty ECU
• Faulty coolant temperature sensor
EAS2GB2418OVERCOOLING
Cooling system
1. Coolant temperature sensor
• Faulty coolant temperature sensor
EAS2GB2419POOR BRAKING PERFORMANCE
Chassis
1. Brake(s)
• Worn brake pad
• Worn brake disc
• Air in hydraulic brake system
• Leaking brake fluid
• Defective master cylinder kit
• Faulty brake caliper kit
• Faulty brake caliper seal
• Loose union bolt
• Damaged brake hose
• Oil or grease on the brake disc
• Oil or grease on the brake pad
• Incorrect brake fluid level
EAS2GB2420FRONT FORK OIL LEAKING
Chassis
1. Front fork
• Bent, damaged, or rusty inner tube
• Cracked or damaged outer tube
• Improperly installed oil seal
• Damaged oil seal lip
• Incorrect oil level (high)
• Loose damper rod assembly bolt
• Damaged damper rod assembly bolt copper
washer
• Cracked or damaged cap bolt O-ring
EAS2GB2421FAULTY FRONT FORK LEGS
Chassis
1. Front fork
• Bent or damaged inner tube
• Bent or damaged outer tube
• Broken fork spring
• Bent or damaged damper rod
• Incorrect oil viscosity
• Incorrect oil level
EAS2GB2422UNSTABLE HANDLING
Chassis
1. Handlebar
• Bent or improperly installed handlebar
2. Steering head components
• Improperly installed upper bracket
• Improperly installed lower bracket
(improperly tightened ring nut)
• Bent steering stem
• Damaged ball bearing or bearing race
3. Front fork leg (s)
• Uneven oil levels (both front fork legs)
• Unevenly tensioned fork spring (both front
fork legs)
• Broken fork spring
• Bent or damaged inner tube
• Bent or damaged outer tube
4. Swingarm
• Worn bearing or bushing
• Bent or damaged swingarm
5. Rear shock absorber assembly (-ies)
• Faulty rear shock absorber spring
• Leaking oil or gas
6. Tire (s)
• Uneven tire pressures (front and rear)
• Incorrect tire pressure
• Uneven tire wear
7. Wheel (s)
• Incorrect wheel balance
• Broken or loose spoke
• Damaged wheel bearing
• Bent or loose wheel axle
• Excessive wheel runout
8. Frame
• Bent frame
• Damaged steering head pipe
• Improperly installed bearing race