clutch YAMAHA WR 450F 2007 Service Manual

4 - 98
ENGCRANKCASE AND CRANKSHAFT
REMOVAL POINTS
Crankcase
1. Separate:
Crankcase (right)
Crankcase (left)
Separation steps:
Remove the crankcase bolts, hose guide
and clutch cable holder.
NOTE:
Loosen each bolt 1/4 of a turn at a time and
after all the bolts are loosened, remove
them.
Remove the crankcase (right).
NOTE:
Place the crankcase with its left side
downward and split it by inserting a screw-
driver tip into the splitting slit a in the
crankcase.
Lift the crankcase (right) horizontally while
lightly patting the case splitting slit and
engine mounting boss using a soft ham-
mer, and leave the crankshaft and trans-
mission with the crankcase (left).
CAUTION:
Use soft hammer to tap on the case half.
Tap only on reinforced portions of case.
Do not tap on gasket mating surface.
Work slowly and carefully. Make sure the
case halves separate evenly. If the cases
do not separate, check for a remaining
case screw or fitting. Do not force.
Remove the dowel pins and O-ring.
a
Balancer shaft
1. Remove:
Balancer shaft 1
NOTE:
Remove the balancer shaft with its flat side a
facing the crankshaft.

4 - 103
ENGCRANKCASE AND CRANKSHAFT
5. Install:
Dowel pin 1
O-ring 2
Crankcase (right)
To crankcase (left).
NOTE:
Fit the crankcase (right) onto the crankcase
(left). Tap lightly on the case with soft ham-
mer.
When installing the crankcase, the connect-
ing rod should be positioned at TDC (top
dead center).
New
6. Tighten:
Hose guide 1
Clutch cable holder 2
Bolt (clutch cable holder)
Bolt (crankcase)
NOTE:
Tighten the crankcase tightening bolts in
stage, using a crisscross pattern.
7. Install:
Timing chain
Timing chain guide (rear)
Bolt (timing chain guide)
8. Remove:
Sealant
Forced out on the cylinder mating surface.
9. Apply:
Engine oil
To the crank pin, bearing and oil delivery
hole.
10. Check:
Crankshaft and transmission operation.
Unsmooth operation → Repair.
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
T R..12 Nm (1.2 m · kg, 8.7 ft · lb)
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)

5 - 39
CHAS
EC5B0000
HANDLEBAR
Extent of removal:
1 Handlebar removal
Extent of removal Order Part name Q’ty Remarks
HANDLEBAR REMOVAL
Preparation for removal Headlight
1 Hot starter cable 1 Disconnect at the lever side.
2 Hot starter lever holder 1
3 Clutch cable 1 Disconnect at the lever side.
4 Clutch lever holder 1 Disconnect the clutch switch lead.
5“ENGINE STOP” button 1 Disconnect the “ENGINE STOP” button
lead.
6 Master cylinder 1 Refer to “REMOVAL POINTS”.
7 Start switch 1 Disconnect the start switch lead.
8 Throttle cable cap 1
9 Throttle cable #1 (pulled) 1 Disconnect at the throttle side.
10 Throttle cable #2 (pushed) 1 Disconnect at the throttle side.
11 Grip (right) 1 Refer to “REMOVAL POINTS”.
12 Tube guide 1
13 Grip (left) 1 Refer to “REMOVAL POINTS”.
14 Handlebar holder (upper) 2
15 Handlebar 1
16 Handlebar holder (lower) 2
1
HANDLEBAR

5 - 44
CHASHANDLEBAR
10. Install:
•Start switch 1
•Master cylinder 2
•Master cylinder bracket 3
•Bolt (master cylinder bracket) 4
•Clamp 5
NOTE:
•The start switch and master cylinder bracket
should be installed according to the dimen-
sions shown.
•Install the bracket so that the arrow mark a
faces upward.
•First tighten the bolt on the upper side of the
master cylinder bracket, and then tighten the
bolt on the lower side.
T R..9 Nm (0.9 m · kg, 6.5 ft · lb)
Zero mm
(Zero in)Zero mm
(Zero in)
11. Install:
•“ENGINE STOP” button 1
•Clutch lever holder 2
•Bolt (clutch lever holder) 3
•Hot starter lever holder 4
•Bolt (hot starter lever holder) 5
•Clamp 6
NOTE:
•The “ENGINE STOP” button, clutch lever
holder and clamp should be installed accord-
ing to the dimensions shown.
•Pass the “ENGINE STOP” button lead in the
middle of the clutch lever holder.
T R..4 Nm (0.4 m · kg, 2.9 ft · lb)
T R..4 Nm (0.4 m · kg, 2.9 ft · lb)
12. Install:
•Clutch cable 1
•Hot starter cable 2
NOTE:
Apply the lithium soap base grease on the
clutch cable end and hot starter cable end.

5 - 45
CHAS
13. Adjust:
•Clutch lever free play
Refer to “CLUTCH ADJUSTMENT” sec-
tion in the CHAPTER 3.
•Hot starter lever free play
Refer to “HOT STARTER LEVER
ADJUSTMENT” section in the CHAPTER
3.
HANDLEBAR

5 - 51
CHASSTEERING
9. Install:
•Plain washer 1
•Steering shaft nut 2
T R..145 Nm (14.5 m · kg, 105 ft · lb)
10. After tightening the nut, check the steering
for smooth movement. If not, adjust the
steering by loosening the ring nut little by
little.
11. Adjust:
•Front fork top end a
Front fork top end (standard)
a:
Zero mm (Zero in)
12. Tighten:
•Pinch bolt (handle crown) 1
•Pinch bolt (under bracket) 2
CAUTION:
Tighten the under bracket to specified
torque. If torqued too much, it may cause
the front fork to malfunction.
13. Install:
•Multi-function meter bracket 1
•Multi-function meter 2
NOTE:
Pass the throttle cables 3, clutch cable 4 and
hot starter cable 5 between the multi-function
meter bracket and handle crown.
14. Install:
•Holder 1
•Clamp 2
NOTE:
•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.
T R..21 Nm (2.1 m · kg, 15 ft · lb)
T R..21 Nm (2.1 m · kg, 15 ft · lb)
T R..7 Nm (0.7 m · kg, 5.1 ft · lb)
T R..4 Nm (0.4 m · kg, 2.9 ft · lb)
T R..13 Nm (1.3 m · kg, 9.4 ft · lb)
T R..7 Nm (0.7 m · kg, 5.1 ft · lb)

6 - 1
–+ELECELECTRICAL COMPONENTS AND WIRING DIAGRAM
EC600000
ELECTRICAL
EC610000
ELECTRICAL COMPONENTS AND WIRING DIAGRAM
EC611000
ELECTRICAL COMPONENTS
1Headlight
2Multi-function display
3“ENGINE STOP” but-
ton
4Clutch switch
5Diode
6Starter relay diode
7TPS (throttle posi-
tion sensor)
8Starter relay
9Fuse
0Starting circuit cut-off
relayACDI unit
BTaillight
CNeutral switch
DStarter motor
EAC magneto
FRectifier/regulator
GIgnition coil
HSpark plug
IStart switch
JMain switch
KSpeed sensor
LBatteryCOLOR CODE
B ...................... Black
Br ..................... Brown
Ch .................... Chocolate
Dg .................... Dark green
G ...................... Green
Gy .................... Gray
L....................... Blue
O ...................... Orange
R ...................... Red
Sb .................... Sky blue
EC612000
WIRING DIAGRAM
W ..................... White
Y ...................... Yellow
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

6 - 6
–+ELEC
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 fol-
lowing conditions is met:
•The transmission is in neutral (the neutral
switch is closed).
•The clutch lever is pulled to the handlebar
(the clutch switch is closed).
The starting circuit cut-off relay prevents the
starter motor from operating when neither of
these conditions has been met. In this
instance, the starting circuit cut-off relay is
open so current cannot reach the starter
motor. When at least one of the above condi-
tions has been met the starting circuit 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 HANDLEBAR
1Battery
2Main fuse
3Main switch
4Starting circuit cut-off relay
5Start switch
6Diode
7Clutch switch
8Neutral switch
9Starter relay
0Starter motor
12
M
3
4
5
8 76 9
0
ELECTRIC STARTING SYSTEM

–+ELEC
6 - 7
ELECTRIC STARTING SYSTEM
INSPECTION STEPS
If the starter motor will not operate, use the following inspection steps.
*1 marked: Refer to “FUSE INSPECTION” section in the CHAPTER 3.
*2 marked: Refer to “BATTERY INSPECTION AND CHARGING” section in the CHAPTER 3.
*3 marked: Refer to “MAIN SWITCH INSPECTION” section.
*4 marked: Refer to “NEUTRAL SWITCH INSPECTION” section.
NOTE:
•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.Replace fuse and
check wire harness.
*2 Check battery. Recharge or replace.
Check each coupler and
wire connection.Repair or replace.
*3 Check main switch. Replace.
Check starter motor
operation.Repair or replace.
Check starting circuit
cut-off relay.Replace.
Check starter relay. Replace.
*4 Check neutral switch. Replace.
Check clutch switch. Replace.
Check diode. Replace.
Check start switch. Replace.
OK
OK
OK
OK
OK
OK
OK
OK
OK
OK
No good
No good No good
No good
No good No good
No good
No goodNo good
No good
No good
Pocket tester:
YU-3112-C/90890-03112

6 - 9
–+ELECELECTRIC STARTING SYSTEM
STARTER RELAY INSPECTION
1. Remove:
•Starter relay
2. Inspect:
•Starter relay conduct
Use 12 V battery.
Continuous while not connected to the battery
→ Replace.
Not continuous while connected to the battery
→ Replace. Battery (+) lead
→
Starter relay terminal
1
Battery (–) lead
→
Starter relay terminal
2
Tester (+) lead
→ Starter relay terminal
3
Tester (–) lead
→ Starter relay terminal
4
Ter-
minal
3
Ter-
minal

4 Tester selec-
tor position
Con-
nected to
battery
Ω
× 1
Not con-
nected to
battery
CLUTCH SWITCH INSPECTION
1. Inspect:
•Clutch switch continuity
No continuous while being pulled → Replace.
Continuous while being freed → Replace. Tester (+) lead
→ Black lead
1
Tester (–) lead
→ Black lead
2
B
1 B
2 Tester selec-
tor position
PULL
Ω
× 1
FREE