Yamaha Wr250r 2008 Manual

							 
ELECTRICAL COMPONENTS 
8-70 
tery cool before reconnecting it. Hot
batteries can explode! 
 
As shown in the following illustration, the
open-circuit voltage of an MF battery stabi-
lizes about 30 minutes after charging has
been completed. Therefore, wait 30 min-
utes after charging is completed before 
measuring the open-circuit voltage.

 
Charging method using a variable-current
(voltage) charger 
a. Measure the open-circuit voltage prior to
charging.
NOTE:
 
Voltage should be measured 30 minutes after 
the machine is stopped.
b. Connect a charged and AMP meter to the
battery and start charging.
NOTE:
 
Set the charging voltage at 16 
– 
17 V.If the setting
is lower, charging will be insufficient. If too high, 
the battery will be over-charged.
c. Make sure that the current is higher than the
standard charging current written on the bat-
tery.
NOTE:
 
If the current is lower than the standard charging
current written on the battery, set the charging
voltage adjust dial at 20 
– 
24 V and monitor the 
amperage for 3 
– 
5 minutes to check the battery.d. Adjust the voltage so that the current is at the
standard charging level.
e. Set the time according to the charging time
suitable for the open-circuit voltage.
Refer to “Battery condition checking steps”.
f. If charging requires more than 5 hours, it is
advisable to check the charging current after
a lapse of 5 hours. If there is any change in
the amperage, readjust the voltage to obtain
the standard charging current.
g. Measure the battery open-circuit voltage af-
ter leaving the battery unused for more than
30 minutes.


 
Charging method using a constant voltage
charger 
a. Measure the open-circuit voltage prior to
charging.
NOTE:
 
Voltage should be measured 30 minutes after 
the machine is stopped.
b. Connect a charger and AMP meter to the bat-
tery and start charging.
c. Make sure that the current is higher than the
standard charging current written on the bat-
tery.
NOTE:
 
If the current is lower than the standard charging
current written on the battery, This type of bat-
tery charger cannot charge the MF battery. A 
variable voltage charger is recommended.
d. Charge the battery until the battery’s charg-
ing voltage is 15 V.
NOTE:
 
Set the charging time at 20 hours (maximum).
e. Measure the battery open-circuit voltage af-
ter leaving the battery unused for more than
30 minutes.

 
A. Open-circuit voltage
B.  Charging the open-circuit voltage
C. Temperature 20 
° 
C 
Reach the standard charging current
Battery is good.
Does not reach the standard charging
current
Replace the battery.
A
BC
 
12.8 V or more --- Charging is complete.
12.7 V or less --- Recharging is required.
Under 12.0 V --- Replace the battery.
12.8 V or more --- Charging is complete.
12.7 V or less --- Recharging is required.
Under 12.0 V --- Replace the battery. 
						

							 
ELECTRICAL COMPONENTS 
8-71 
6. Check: 
 
Battery terminals
Dirt  
→ 
 Clean with a wire brush.
Loose connection  
→ 
 Connect properly.
7. Install: 
 
Battery
8. Connect: 
 
Battery leads
(to the battery terminals)
9. Lubricate: 
 
Battery terminals
10.Install: 
 
Battery band
11.Install: 
 
Side cover (left)
Refer to “GENERAL CHASSIS” on page 4-1. 
EAS28040 
CHECKING THE RELAYS 
Check each switch for continuity with the pocket
tester. If the continuity reading is incorrect, re-
place the relay.
1. Disconnect the relay from the wire harness.
2. Connect the pocket tester ( 
Ω 
  
× 
 1) and battery
(12 V) to the relay terminal as shown.
Check the relay operation.
Out of specification  
→ 
 Replace. 
Starter relayRelay unit (starting circuit cut-off relay)
Relay unit (fuel pump) Recommended lubricant
Dielectric grease
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C 
1.  Positive battery terminal
2.  Negative battery terminal
3.  Positive tester probe
4.  Negative tester probe
21 3
4
 
Result
Continuity
(between “3” to “4”) 
1.  Positive battery terminal
2.  Negative battery terminal
3.  Positive tester probe
4.  Negative tester probe 
Result
Continuity
(between “3” to “4”) 
1.  Positive battery terminal
2.  Negative battery terminal
3.  Positive tester probe
4.  Negative tester probe 
Result
Continuity
(between “3” to “4”)
5143672
1
2
34 
						

							 
ELECTRICAL COMPONENTS 
8-72 
Headlight relay
Checking the turn signal relay

 
a. Check: 
 
Turn signal relay input voltage
Off specification  
→ 
Repair wire harness con-
nection failure from main switch to turn signal
relay coupler

 
a. Connect the pocket tester (DC 20 V) to the
turn signal relay terminal.b. Turn the main switch to “ON”.
c. Measure turn signal relay applied voltage.

 
d. Check: 
 
Turn signal relay output voltage
Out of specification   
→  
 Replace the defective
part (s).

 
a. Connect the pocket tester (DC 20 V) to the
turn signal relay terminal.
b. Turn the main switch to “ON”.
c. Measure turn signal relay applied voltage.

 
1.  Positive battery terminal
2.  Negative battery terminal
3.  Positive tester probe
4.  Negative tester probe 
Result
Continuity
(between “3” to “4”)
Turn signal relay input voltage
DC 12V
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
Tester positive probe
Red/Blue  
“ 
1 
” 
Negative tester probe
Ground
1 23
4
 
Turn signal relay output voltage
DC 12V
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
Tester positive probe
Brown/White termnals   
“  
1  
”  
Negative tester probe
Ground
1
1 
						

							 
ELECTRICAL COMPONENTS 
8-73 
Radiator fan motor relay 
EAS28050 
CHECKING THE DIODE 
1. Check: 
 
Diode
Out of specification  
→ 
 Replace.
NOTE:
 
The pocket tester and the analog pocket tester 
readings are shown in the following table.

 
a. Disconnect the starting circuit cut-off relay
from the wire harness.
b. Connect the pocket tester (  
Ω  
   
×  
 1) to the start-
ing circuit cut-off relay coupler as shown. 
1.  Positive battery terminal
2.  Negative battery terminal
3.  Positive tester probe
4.  Negative tester probe 
Result
Continuity
(between “3” to “4”)
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
1 23
4
 
Continuity
Tester positive lead   
→  
 Sky blue
“1”
Tester negative lead   
→  
 Light
green “2”
No continuity
Tester positive lead   
→  
 Light
green “2”
Tester negative lead   
→  
 Sky blue
“1”
Continuity
Tester positive lead   
→  
 Blue/
Green “3”
Tester negative lead   
→  
 Blue/Yel-
low “4”
No continuity
Tester positive lead   
→  
 Blue/Yel-
low “4”
Tester negative lead   
→  
 Blue/
Green “3”
Continuity
Tester positive lead   
→  
 Sky blue
“1”
Tester negative lead   
→  
 Blue/Yel-
low “4”
No continuity
Tester positive lead   
→  
 Blue/Yel-
low “4”
Tester negative lead  
→  
 Sky blue
“1”
Continuity
Tester positive lead  
→  
 Sky blue
“1”
Tester negative lead  
→  
 Black/
Yellow “5”
No continuity
Tester positive lead  
→  
 Black/
Yellow “5”
Tester negative lead  
→  
 Sky blue
“1”
Continuity
Tester positive lead  
→  
 Brown
“6”
Tester negative lead  
→  
 Blue/
White “7”
No continuity
Tester positive lead  
→  
 Blue/
White “7”
Tester negative lead  
→  
 Brown
“6” 
						

							 
ELECTRICAL COMPONENTS 
8-74 
c. Check the diode for continuity.
d. Check the diode for no continuity.

 
EAS28930 
CHECKING THE IGNITION SPARK GAP 
1. Check: 
 
Ignition spark gap
Out of specification  
→ 
 Perform the ignition
system troubleshooting, starting with step *.
Refer to “TROUBLESHOOTING” on page
8-3.
NOTE:
 
If the ignition spark gap is within specification, 
the ignition system circuit is operating normally.

 
a. Disconnect the spark plug cap from the spark
plug.
b. Connect the ignition checker “1” as shown.c. Turn the main switch to “ON” and engine stop
switch to “”.
d. Measure the ignition spark gap “a”.
e. Crank the engine by pushing the start switch
“” and gradually increase the spark gap un-
til a misfire occurs.

 
EAS28090 
CHECKING THE IGNITION COIL  
1. Check: 
 
Primary coil resistance
Out of specification   
→  
 Replace.

 
a. Disconnect the ignition coil lead coupler from
wire harness.
b. Connect the pocket tester ( 
Ω  
   
×  
 1) to the igni-
tion coil as shown.
c. Measure the primary coil resistance.

 
2. Check: 
 
Secondary coil resistance
Out of specification  
→  
 Replace.  
Minimum ignition spark gap
6.0 mm (0.24 in)
Ignition checker
90890-06754
Opama pet-4000 spark checker
YM-34487 
1. Ignition checker
2.  Spark plug cap
5143672
 
Primary coil resistance
1.19  
–  
1.61   
Ω  
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
Tester positive probe
Red/Black termainal  
“  
1  
”  
Negative tester probe
Orange terminal  
“  
2  
” 
						

							 
ELECTRICAL COMPONENTS 
8-75

 
a. Disconnect the spark plug cap from the igni-
tion coil.
b. Connect the pocket tester ( 
Ω 
  
× 
 1k) to the ig-
nition coil as shown.
c. Measure the secondary coil resistance.

 
EAS32D1002 
CHECKING THE CRANKSHAFT POSITION 
SENSOR 
1. Disconnect: 
 
Crankshaft position sensor coupler
(from the wire harness)
2. Check: 
 
Crankshaft position sensor resistance
Out of specification  
→ 
 Replace the crank-
shaft position sensor.

 
a. Connect the pocket tester ( 
Ω 
  
× 
 100) to the
crankshaft position sensor coupler as shown.b. Measure the crankshaft position sensor re-
sistance.

 
EAS28130 
CHECKING THE LEAN ANGLE SENSOR 
1. Remove: 
 
Lean angle sensor
(from the bracket.)
2. Check: 
 
Lean angle sensor out put voltage
Out of specification  
→  
 Replace.

 
a. Connect the lean angle sensor coupler to the
wireharness.
b. Connect the pocket tester (DC 20 V) to the
lean angle sensor coupler as shown. 
Secondary coil resistance
8.50 
– 
11.50 k 
Ω 
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
Positive tester probe
Red/Black  
“ 
1 
” 
Negative tester probe
Spark plug lead  
“ 
2 
” 
Crankshaft position sensor resis-
tance
248 
– 
372  
Ω 
 (R 
– 
W) 
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
Positive tester probe
Red  
“ 
1 
” 
Negative tester probe
White  
“ 
2 
” 
Lean angle sensor out put voltage
Less than 65 
°  
 “a” 0.4  
–  
1.4V
More than 65 
°  
 “b” 3.7  
–  
4.4V
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
12 
						

							 
ELECTRICAL COMPONENTS 
8-76 
c. Incline the lean angle sensor.
d. Measure the lean angle sensor out put volt-
age.

 
EAS28150 
CHECKING THE STATOR COIL 
1. Disconnect: 
 
Stator coil coupler
(from the wire harness)
2. Check: 
 
Stator coil resistance
Out of specification  
→ 
 Replace the stator coil.

 
a. Connect the pocket tester ( 
Ω 
  
× 
 1) to the stator
coil coupler as shown.b. Measure the stator coil resistance.

 
EAS28170 
CHECKING THE RECTIFIER/REGULATOR  
1. Check: 
 
Charging voltage
Out of specification   
→  
 Replace the rectifier/
regulator.

 
a. Set the digital tachometer to the ignition coil
of cylinder #1.
b. Connect the pocket tester (DC 20 V) to the
rectifier/regulator coupler as shown.  
Tester positive probe
Blue  
“ 
1 
” 
Negative tester probe
Yellow/Green  
“ 
2 
” 
Stator coil resistance
0.168 
– 
0.252  
Ω 
 (W-W)
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
Positive tester probe
White  
“ 
1 
” 
Negative tester probe
White  
“ 
2 
” 
Positive tester probe
White  
“ 
1 
” 
Negative tester probe
White  
“ 
3 
”
1
2
aa
bON ON
 
Positive tester probe
White  
“ 
2 
” 
Negative tester probe
White  
“ 
3 
” 
Charging voltage
14 V at 5000 r/min
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
Positive tester probe
Positive battery terminal  
“  
1  
”  
Negative tester probe
Negative battery terminal  
“  
2  
”
13
2 
						

							 
ELECTRICAL COMPONENTS 
8-77 
c. Start the engine and let it run at approximate-
ly 5000 r/min.
d. Measure the charging voltage.

 
EAS28180 
CHECKING THE HORN 
1. Check: 
 
Horn resistance
Out of specification  
→ 
 Replace.

 
a. Disconnect the horn leads from the horn ter-
minals.
b. Connect the pocket tester ( 
Ω 
  
× 
 1) to the horn
terminals.
c. Measure the horn resistance.

 
2. Check: 
 
Horn sound
Faulty sound   
→  
 Adjust or replace.

 
a. Connect a battery (12 V) to the horn.
b. Turn the adjusting screw in direction “a” or “b”
until the specified horn sound is obtained.

 
EAS28240 
CHECKING THE SPEED SENSOR 
1. Check: 
 
Speed sensor output voltage
Out of specification   
→  
 Replace.

 
a. Connect the pocket tester (DC 20 V) to the
speed sensor coupler (wire harness side) as
shown. 
Horn resistance
1.01 
– 
1.11  
Ω 
 at 20 
° 
C (68 
° 
F)
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
Positive tester probe
Horn terminal  
“ 
1 
” 
Negative tester probe
Horn terminal  
“ 
2 
”
12
1
2
 
Output voltage reading cycle
0 V 
– 
5 V 
–  
0 V  
–  
5 V  
–  
0 V
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
Positive tester probe
White  
“ 
1 
” 
Negative tester probe
Black/Blue  
“ 
2 
”
ab 
						

							 
ELECTRICAL COMPONENTS 
8-78 
b. Set the main switch to “ON”.
c. Elevate the rear wheel and slowly turn it.
d. Measure the voltage (DC 5 V) of white and
black/blue. With the front wheel slowly rotat-
ing, voltage alternates between 0 V and 5 V.

 
EAS32D1012 
CHECKING THE FUEL SENDER (FUEL 
PUMP) 
Drain the gasoline.
1. Disconnect: 
 
Fuel pump coupler
(from the fuel pump)
2. Remove: 
 
Fuel pump
(from the fuel pump tank)
3. Check: 
 
Fuel sender resistance
Out of specification  
→ 
 Replace the fuel
pump.

 
a. Connect the pocket tester (k 
Ω 
  
× 
 1) to the fuel
sender as shown.b. Measure the resistance of the fuel sender.

 
EAS28260 
CHECKING THE COOLANT TEMPERATURE 
SENSOR  
1. Remove: 
 
Coolant temperature sensor
Refer to “THERMOSTAT” on page 6-4.
WARNING
 
EWA14130  
 
Handle the coolant temperature sensor
with special care. 
 
Never subject the coolant temperature sen-
sor to strong shocks. If the coolant temper- 
ature sensor is dropped, replace it. 
2. Check: 
 
Coolant temperature sensor resistance
Out of specification  
→  
 Replace.

 
a. Connect the pocket tester ( 
Ω  
   
×  
 100) to the
coolant temperature sensor as shown. 
Fuel sender resistance
0.94 
– 
1.88 k 
Ω 
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
Positive tester probe
Green/White  
“ 
1 
” 
Negative tester probe
Black  
“ 
2 
”
21
 
 Resistance 20 
°  
C (68  
°  
F)
2.32 
– 
2.59 k 
Ω 
 Resistance 80 
°  
C (176  
°  
F)
310 
– 
326  
Ω 
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
Positive tester probe
Black “1”
Negative tester probe
Black “2”
12 
						

							 
ELECTRICAL COMPONENTS 
8-79 
b. Immerse the coolant temperature sensor in a
container filled with coolant.
NOTE:
 
Make sure the coolant temperature sensor ter- 
minals do not get wet.
c. Place a thermometer in the coolant.
d. Slowly heat the coolant, and then let it cool to
the specified temperature indicated in the ta-
ble.
e. Check the coolant temperature sensor for
continuity at the temperatures indicated in
the table.

 
EAS28250 
CHECKING THE RADIATOR FAN MOTOR 
1. Check: 
 
Radiator fan motor
Faulty/rough movement  
→ 
 Replace.

 
a. Disconnect the radiator fan motor couplerfrom the wire harness.
b. Connect the battery (DC 12 V) as shown.
c. Measure the radiator fan motor movement.

 
EAS28300 
CHECKING THE THROTTLE POSITION 
SENSOR  
1. Check: 
 
Throttle position sensor

 
a. Connect the pocket tester (DC 20 V) to the
throttle position sensor as shown.
b. While slowly turning the throttle position sen-
12
 
Positive tester probe
Blue   
“  
1  
”  
Negative tester probe
Black   
“  
2  
”  
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
Tester positive lead  
→  
Yellow  
“  
1  
”  
Tester negative lead  
→  
Black/Blue  
“  
2  
”
12
12