2008 YAMAHA WR 450F clutch

6-30
STEERING
6. Install:
• Washer "1"
7. Install:
• Front fork "1"
• Upper bracket "2"
• Main switch "3"
• Front brake hose guide bracket
"4"
• Temporarily tighten the pinch bolts
(lower bracket).
• Do not tighten the pinch bolts (up-
per bracket) yet.
8. Install:
• Guide (speed sensor lead) "1"
After installing the guide as shown,
pass the speed sensor lead through
the guide.
9. Install:
• Washer "1"
• Steering stem nut "2"10. After tightening the nut, check the
steering for smooth movement. If
not, adjust the steering by loosen-
ing the steering ring nut little by lit-
tle.
11. Adjust:
• Front fork top end "a"
12. Tighten:
• Pinch bolt (upper bracket) "1"
• Pinch bolt (lower bracket) "2"
Tighten the lower bracket to speci-
fied torque. If torqued too much, it
may cause the front fork to mal-
function.
13. Install:
• Multi-function display bracket "1"
• Multi-function display "2"
Pass the throttle cables "3", clutch ca-
ble "4" and hot starter cable "5" be-
tween the multi-function display
bracket and upper bracket.
14. Install:
• Holder "1"
• Clamp "2"
• Install so that the marking "a" on the
speed sensor lead aligns with the
holder edge.
• Fasten the speed sensor lead to the
holder with the clamp.
Steering stem nut:
145 Nm (14.5 m•kg, 105
ft•lb)
Front fork top end (stan-
dard) "a":
Zero mm (Zero in)
Pinch bolt (upper brack-
et):
21 Nm (2.1 m•kg, 15
ft•lb)
Pinch bolt (lower brack-
et):
21 Nm (2.1 m•kg, 15
ft•lb)
Multi-function display
bracket:
7 Nm (0.7 m•kg, 5.1
ft•lb)
Multi-function display:
4 Nm (0.4 m•kg, 2.9
ft•lb)
Holder:
13 Nm (1.3 m•kg, 9.4
ft•lb)
Clamp:
7 Nm (0.7 m•kg, 5.1
ft•lb)

7-1
ELECTRICAL COMPONENTS AND WIRING DIAGRAM
ELECTRICAL
ELECTRICAL
COMPONENTS AND
WIRING DIAGRAM
ELECTRICAL COMPONENTS
1. Headlight
2. Multi-function display
3. Engine stop switch
4. Clutch switch
5. Diode
6. Starter relay diode
7. Throttle position sensor
8. Starter relay9. Fuse
10. Starting circuit cut-off relay
11. CDI unit
12. Taillight
13. Neutral switch
14. Starter motor
15. AC magneto
16. Rectifier/regulator17. Ignition coil
18. Spark plug
19. Start switch
20. Main switch
21. Speed sensor
22. Battery

7-2
ELECTRICAL COMPONENTS AND WIRING DIAGRAM
WIRING DIAGRAM
1. Headlight
2. Multi-function display
3. Engine stop switch
4. Clutch switch
5. Diode
6. Starter relay diode
7. Throttle position sensor
8. Starter relay
9. Fuse
10. Starting circuit cut-off relay
11. CDI unit
12. Taillight
13. Neutral switch
14. Starter motor
15. AC magneto
16. Rectifier/regulator
17. Ignition coil
18. Spark plug
19. Start switch
20. Main switch
21. Speed sensor
22. Battery
*1: For USA
*2: Except for USACOLOR CODE
BBlack
Br Brown
Ch Chocolate
Dg Dark green
GGreen
Gy Gray
LBlue
O Orange
RRed
Sb Sky blue
WWhite
YYellow
B/L Black/Blue
B/W Black/White
L/B Blue/Black
L/R Blue/Red
L/Y Blue/Yellow
L/W Blue/White
R/B Red/Black
R/W Red/White


7

7-5
ELECTRIC STARTING SYSTEM
4. Inspect:
• Sealed portion of ignition coil "a"
• Spark plug terminal pin "b"
• Threaded portion of spark plug "c"
Wear →Replace.
CHECKING THE AC MAGNETO
1. Inspect:
• Pickup coil resistance
Out of specification→Replace.
CHECKING THE NEUTRAL
SWITCH
1. Inspect:
• Neutral switch conduction
Not conductive while it is in neutral→
Replace.
Conductive while it is engaged→Re-
place.
Set the tester selection position to "Ω
× 1".
CHECKING THE CDI UNIT
Check all electrical components. If no
fault is found, replace the CDI unit.
Then check the electrical compo-
nents again.
ELECTRIC STARTING
SYSTEM
STARTING CIRCUIT CUT-OFF
SYSTEM OPERATION
If the main switch is set to "ON", the
starter motor can only operate if at
least one of the following conditions is
met:
• The transmission is in neutral (the
neutral switch is closed).
• The clutch lever is pulled to the han-
dlebar (the clutch switch is closed).
The starting circuit cut-off relay pre-
vents the starter motor from operating
when neither of these conditions has
been met. In this instance, the start-
ing circuit cut-off relay is open so cur-
rent cannot reach the starter motor.
When at least one of the above con-
ditions has been met the starting cir-
cuit cut-off relay is closed and the
engine can be started by pressing the
start switch.
WHEN THE TRANSMISSION IS IN
NEUTRAL
WHEN THE CLUTCH LEVER IS
PULLED TO THE HANDLEBAR1. Battery
2. Main fuse
3. Main switch
4. Starting circuit cut-off relay
5. Start switch
6. Diode
7. Clutch switch
8. Neutral switch
9. Starter relay
10. Starter motor Tester (+) lead→Red lead "1"
Tester (-) lead→White lead "2"
Pickup coil
resistanceTester se-
lector posi-
tion
248–372 Ω
at 20 °C (68
°F) Ω × 100
Tester (+) lead→Sky blue lead "1"
Tester (-) lead→Ground "2"
Result
Conductive (while gear
is in neutral)

7-6
ELECTRIC STARTING SYSTEM
INSPECTION STEPS
If the starter motor will not operate, 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.
*3 marked: Refer to "CHECKING THE MAIN SWITCH" section.
*4 marked: Refer to "CHECKING THE NEUTRAL SWITCH" section.
• Remove the following parts before inspection.
1. Seat
2. Rear fender
• Use 12 V battery in this inspection.
• 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↓
*3 Check main switch. No good→Replace.
OK↓
Check starter motor operation. No good→Repair or replace.
OK↓
Check starting circuit cut-off relay. No good→Replace.
OK↓
Check starter relay. No good→Replace.
OK↓
*4 Check neutral switch. No good→Replace.
OK↓
Check clutch switch. No good→Replace.
OK↓
Check diode. No good→Replace.
OK↓
Check start switch. No good→Replace.
Pocket tester:
YU-3112-C/90890-03112

7-7
ELECTRIC STARTING SYSTEM
CHECKING THE COUPLERS AND
LEADS CONNECTION
1. Check:
• Couplers and leads connection
Rust/dust/looseness/short-circuit
→Repair or replace.
CHECKING THE STARTER
MOTOR OPERATION
1. Connect the positive battery ter-
minal "1" and starter motor lead
"2" with a jumper lead "3".
Not operate→Repair or replace
the starter motor.
• A wire that is used as a jumper
lead must have at least the same
capacity or more as that of the
battery lead, otherwise the jump-
er lead may burn.
• This check is likely to produce
sparks, therefore make sure
nothing flammable is in the vicin-
ity.
CHECKING THE STARTING
CIRCUIT CUT-OFF RELAY
1. Remove:
• Starting circuit cut-off relay
2. Inspect:
• Starting circuit cut-off relay con-
duction
Use 12 V battery.
Not conductive while the battery is
connected→Replace.
Conductive while the battery is not
connected→Replace.
Set the tester selection position to "Ω
× 1".
CHECKING THE STARTER RELAY
1. Remove:
• Starter relay
2. Inspect:
• Starter relay conduction
Use 12 V battery.
Not conductive while the battery is
connected→Replace.
Conductive while the battery is not
connected →Replace.
Set the tester selection position to "Ω
× 1".
CHECKING THE CLUTCH SWITCH
1. Inspect:
• Clutch switch conduction
Not conductive while it is pulled→Re-
place.
Conductive while it is freed→Re-
place.
Set the tester selection position to "Ω
× 1".
CHECKING THE DIODE
1. Remove the diode from wire har-
ness.
2. Inspect:
• Diode continuity
Use pocket tester (tester selec-
tion position Ω × 1)
Incorrect continuity→Replace.
CHECKING THE START SWITCH
1. Inspect:
• Start switch conduction
Not conductive while it is pushed→
Replace.
Conductive while it is freed→Re-
place.
Set the tester selection position to "Ω
× 1".
Battery (+) lead→Blue/Black lead
"1"
Battery (-) lead→Brown lead "2"
Tester (+) lead→Blue/White lead
"3"
Tester (-) lead→Black lead "4"
Result
Conductive (while the
battery is connected)
Battery (+) lead→Starter relay ter-
minal "1"
Battery (-) lead→Starter relay ter-
minal "2"
Tester (+) lead→Starter relay ter-
minal "3"
Tester (-) lead→Starter relay ter-
minal "4"
Result
Conductive (while the
battery is connected)
Tester (+) lead→Black lead "1"
Tester (-) lead→Black lead "2"
Result
Conductive (while the
clutch lever is pulled)
Tester (+)→Blue/Red
terminal "1"
Tester (-) →Sky blue
terminal "2"Continu-
ous
Tester (+)→Blue/Red
terminal "1"
Tester (-)→Blue/Yel-
low terminal "3"Continu-
ous
Tester (+)→Sky blue
terminal "2"
Tester (-)→Blue/Red
terminal "1"No con-
tinuous
Tester (+)→Blue/Yel-
low terminal "3"
Tester (-)→Blue/Red
terminal "1"No con-
tinuous
Tester (+) lead→Black lead "1"
Tester (-) lead→Black lead "2"
Result
Conductive (while the
start switch is pushed)