2008 YAMAHA WR 450F oil

7-13
CHARGING SYSTEM
CHARGING SYSTEM
INSPECTION STEPS
If the battery is not charged, use the following inspection steps.
*1 marked: Refer to "CHECKING THE FUSE" section in the CHAPTER 3.
*2 marked: Refer to "CHECKING AND CHARGING THE BATTERY" section in the CHAPTER 3.
• Remove the following parts before inspection.
1. Seat
2. Fuel tank
• Use the following special tools in this inspection.
*1 Check fuse. No good→Replace fuse and check wire harness.
OK↓
*2 Check battery. No good→Recharge or replace.
OK↓
Check each coupler and wire connection. No good→Repair or replace.
OK↓
Check charging voltage. OK→Charging system is good.
No good↓
Check AC magneto. (Charging coil) No good→Replace.
OK↓
Replace rectifier/regulator.
Pocket tester:
YU-3112-C/90890-03112

7-14
CHARGING SYSTEM
CHECKING THE COUPLERS AND
LEADS CONNECTION
1. Check:
• Couplers and leads connection
Rust/dust/looseness/short-circuit
→Repair or replace.
CHECKING THE CHARGING
VOLTAGE
1. Start the engine.
2. Inspect:
• Charging voltage
Out of specification→If no failure
is found in checking the source
coil resistance, replace the rectifi-
er/regulator.
3. Inspect:
• Charging coil resistance
Out of specification→Replace. Tester (+) lead→Red lead "1"
Tester (-) lead→Black lead "2"
Charging
voltageTester se-
lector posi-
tion
14.0–15.0 V
at 5,000 r/
minDCV-20
Tester (+) lead→White lead "1"
Tester (-) lead→Ground "2"
Charging
coil resis-
tanceTester se-
lector posi-
tion
0.288–0.432
Ω at 20 °C
(68 °F)Ω × 1

7-15
THROTTLE POSITION SENSOR SYSTEM
THROTTLE POSITION SENSOR SYSTEM
INSPECTION STEPS
If the throttle position sensor will not operate, use the following inspection steps.
Use the following special tools in this inspection.
Check entire ignition system for connection. No good→Repair or replace.
OK↓
Check throttle position sensor.(Throttle position
sensor coil)No good→
Replace.
OK↓
Check CDI unit.(Throttle position sensor input
voltage)No good→
Replace.
Pocket tester:
YU-3112-C/90890-03112

7-16
THROTTLE POSITION SENSOR SYSTEM
HANDLING NOTE
Do not loosen the screw (throttle
position sensor) "1" except when
changing the throttle position sen-
sor due to failure because it will
cause a drop in engine perfor-
mance.
CHECKING THE COUPLERS AND
LEADS CONNECTION
1. Check:
• Couplers and leads connection
Rust/dust/looseness/short-circuit
→Repair or replace.
CHECKING THE THROTTLE
POSITION SENSOR COIL
1. Inspect:
• Throttle position sensor coil resis-
tance
Out of specification→Replace.
2. Loosen:
• Throttle stop screw "1"
Turn out the throttle stop screw until
the throttle shaft is in the full close po-
sition.
3. Inspect:
• Throttle position sensor coil vari-
able resistance
Check that the resistance in in-
creased as the throttle grip is
moved from the full close position
to the full open position.
Out of specification→Replace.
CHANGING AND ADJUSTING THE
THROTTLE POSITION SENSOR
1. Remove:
• Throttle position sensor coupler
• Carburetor
2. Remove:
• Screw (throttle position sensor)
"1"
• Throttle position sensor "2"
Loosen the screw (throttle position
sensor) using the T25 bit.
3. Replace:
• Throttle position sensor
4. Install:
• Throttle position sensor "1"
• Screw (throttle position sensor)
"2"
• Align the slot "a" in the throttle posi-
tion sensor with the projection "b"
on the carburetor.
• Temporarily tighten the screw
(throttle position sensor).
5. Install:
•Carburetor
• Throttle position sensor coupler
6. Adjust:
• Engine idling speed
Refer to "ADJUSTING THE EN-
GINE IDLING SPEED" section in
the CHAPTER 3.
7. Insert the thin electric conductors
"2" (lead) into the throttle position
sensor coupler "1", as shown, and
connect the tester to them.
• Do not insert the electric conduc-
tors more than required because
it may reduce the waterproof
function of the coupler.
• Make sure that a short-circuit
does not develop between the
terminals because it may cause
damage to electrical compo-
nents.
8. Start the engine.
9. Adjust:
• Throttle position sensor output
voltage
Adjustment steps:
a. Adjust the installation angle of the
throttle position sensor "1" to ob-
tain the specified output voltage. Tester (+) lead→Blue lead "1"
Tester (-) lead→Black lead "2"
Throttle po-
sition sen-
sor coil
resistanceTester se-
lector posi-
tion
4–6 kΩ at
20°C (68 °F) kΩ×1
Tester (+) lead→Yellow lead "1"
Tester (-) lead→Black lead "2"
Throttle position
sensor coil vari-
able resistanceTester
selec-
tor po-
sition
Full
closedFull
opened
kΩ×1 Zero –2
kΩat
20°C
(68 °F)4–6
kΩat
20 °C
(68 °F)
Tester (+) lead→Yellow lead "3"
Tester (-) lead→Black lead "4"

7-18
LIGHTING SYSTEM
LIGHTING SYSTEM
INSPECTION STEPS
Refer to the following flow chart when inspecting the lighting system for possible problems.
• Remove the following parts before inspection.
1. Seat
2. Fuel tank
3. Left side cover
• Use the following special tools in this inspection.
Check the bulb and bulb socket. No good→Replace the bulb and/or bulb socket.
OK↓
Check the taillight (LEDs). No good→Replace the taillight assembly.
OK↓
Check the AC magneto. (Lighting coil) No good→Replace.
OK↓
Check the entire lighting system proper for con-
nections.Improperly
connected→Repair or replace.
OK↓
Check the rectifier/regulator. (Out-put voltage) No good→Replace.
Pocket tester:
YU-3112-C/90890-03112

7-19
LIGHTING SYSTEM
CHECKING THE TAILLIGHT
(LEDs)
1. Disconnect the taillight coupler.
2. Connect two jumper leads "1"
from the battery terminals to the
respective coupler terminal as
shown.
3. Check:
• LED (for proper operation)
Does not light→Replace the tail-
light assembly.
• A wire that is used as a jumper
lead must have at least the same
capacity of the battery lead, oth-
erwise the jumper lead may burn.
• This check is likely to produce
sparks, therefore, make sure no
flammable gas or fluid is in the
vicinity.
CHECKING THE AC MAGNETO
1. Inspect:
• Lighting coil resistance
Out of specification→Replace.CHECKING THE RECTIFIER/
REGULATOR
1. Connect the battery leads.
2. Start the engine.
3. Turn on the headlight and taillight
by turning on the light switch.
4. Inspect:
• Out-put voltage
Out of specification→Replace
rectifier/regulator. Battery (+) terminal→Blue lead
"2"
Battery (-) terminal→Black lead
"3"
Tester (+) lead→Yellow lead "1"
Tester (-) lead→Ground "2"
Light-
ing coil
resis-
tanceTester selector
position
0.224–
0.336 Ω
at 20 °C
(68 °F) Ω × 1
Tester (+) lead→Yellow lead "1"
Tester (-) lead→Black lead "2"
Out-put
voltageTester se-
lector posi-
tion
12.5–13.5 V
at 5,000 r/
minACV-20