oil YAMAHA WR 450F 2011 Repair Manual

5-48
AC MAGNETO AND STARTER CLUTCH
AC MAGNETO AND STARTER CLUTCH
REMOVING THE AC MAGNETO AND STARTER CLUTCH
Order Part name Q'ty Remarks
Drain the engine oil.Refer to "CHANGING THE ENGINE OIL"
section in the CHAPTER 3.
Seat and fuel tankRefer to "REMOVING THE SEAT, FUEL
TANK AND SIDE COVERS" section in the
CHAPTER 3.
Disconnect the AC magneto lead.
1 Shift pedal 1
2 Cover (torque limiter) 1
3 Torque limiter 1 Do not disassemble.
4 Crankcase cover (left) 1
5 Gasket 1
6 Dowel pin 2
7 Idle gear 1
8 Bearing 1
9Shaft 1
10* Nut (rotor) 1 Refer to TIP.
11 Rotor 1 Refer to removal section.

5-49
AC MAGNETO AND STARTER CLUTCH
Tighten the rotor nut to 65 Nm (6.5 m•kg, 47 ft•lb), loosen and retighten the rotor nut to 65 Nm (6.5 m•kg, 47 ft•lb).
12 Woodruff key 1
13 Starter clutch assembly cover 1 Refer to removal section.
14 Starter clutch 1 Refer to removal section.
15 Starter clutch drive gear 1
16 Holder 1
17 Pickup coil 1
18 Stator 1 Order Part name Q'ty Remarks

5-50
AC MAGNETO AND STARTER CLUTCH
REMOVING THE ROTOR
1. Remove:
• Nut (rotor) "1"
• Washer
Use the sheave holder "2".
2. Remove:
• Rotor "1"
Use the rotor puller "2".
REMOVING THE STARTER
CLUTCH
1. Remove:
• Starter clutch assembly cover "1"
Insert a thin screwdriver or the like
under the convexity "a" and remove
the starter clutch assembly cover by
prying it gently to void damage to the
cover.
2. Remove:
• Starter clutch "1"
Using a thin screwdriver or the like,
remove the plate "a" while prying it
upward little by little.
CHECKING THE AC MAGNETO
1. Inspect:
• Rotor inner surface "a"
• Stator outer surface "b"
Damage→Inspect the crankshaft
runout and crankshaft bearing.
If necessary, replace AC magneto
and/or stator.
CHECKING THE WOODRUFF KEY
1. Inspect:
• Woodruff key "1"
Damage→Replace.
CHECKING THE STARTER
CLUTCH
1. Check:
• Starter clutch
Damage/wear→Replace.
2. Check:
• Idle gear
• Idle gear shaft
• Starter clutch drive gear
Pitting/burrs/chips/roughness/
wear→Replace the defective
parts.3. Check:
• Starter clutch operation
a. Install the starter clutch drive gear
"1" onto the starter clutch "2" and
hold the starter clutch.
b. When turning the starter clutch
drive gear counterclockwise "B",
the starter clutch and the starter
clutch drive gear should engage.
If the starter clutch drive gear and
starter clutch do not engage, the
starter clutch is faulty and must be
replaced.
c. When turning the starter clutch
drive gear clockwise "A", it should
turn freely. If the starter clutch
drive gear does not turn freely, the
starter clutch is faulty and must be
replaced.
CHECKING THE TORQUE LIMITER
1. Check:
• Torque limiter
Damage/wear→Replace.
INSTALLING THE AC MAGNETO
AND STARTER CLUTCH
1. Install:
• Stator "1"
• Bolt (stator) "2"
• Pickup coil "3"
• Holder "4"
• Bolt (pickup coil) "5" Sheave holder:
YS-1880-A/90890-
01701
Rotor puller:
YM-04142/90890-04142
Bolt (stator):
7 Nm (0.7 m•kg, 5.1
ft•lb)
Bolt (pickup coil):
10 Nm (1.0 m•kg, 7.2
ft•lb)

5-51
AC MAGNETO AND STARTER CLUTCH
• Pass the AC magneto lead "5" un-
der the pickup coil.
• Pass the AC magneto lead "4" un-
der the holder as shown.
• Take care not to catch the AC mag-
neto lead between crankcase cover
ribs.
• Tighten the bolt (stator) using the
T25 bit.
• Apply the sealant to the grommet of
the AC magneto lead.
2. Install:
• Starter clutch drive gear "1"
Apply the engine oil on the starter
clutch drive gear inner circumference.
3. Install:
• Starter clutch "1"
To rotor "2".
• Install the starter clutch with its
plate side upward.
• While installing the starter clutch,
push in the projections "a" one by
one on the clutch circumference.
• Push in the starter clutch until it hits
the rotor.
4. Install:
• Starter clutch assembly cover "1"
To rotor "2".
Install the starter clutch assembly
cover by fitting its pawls "a" into the
groove "b" in the rotor.
5. Install:
• Woodruff key "1"
• Rotor "2"
• Degrease the contact surfaces of
the tapered portions of the crank-
shaft and rotor.
• When installing the woodruff key,
make sure that its flat surface "a" is
in parallel with the crankshaft center
line "b".
• When installing the rotor, align the
keyway "c" of the rotor with the
woodruff key.
6. Install:
• Washer (rotor)
• Nut (rotor) "1"
Use the sheave holder "2"
Tighten the rotor nut to 65 Nm (6.5
m•kg, 47 ft•lb), loosen and retighten
the rotor nut to 65 Nm (6.5 m•kg, 47
ft•lb).
7. Install:
• Shaft "1"
• Bearing "2"
• Idle gear 2 "3"
Apply the engine oil on the shaft,
bearing and idle gear inner circumfer-
ence.
8. Install:
• Dowel pin
• Gasket [crankcase cover (left)]
• Crankcase cover (left) "1"
• Bolt [crankcase cover (left)]
Tighten the bolts in stage, using a
crisscross pattern.
9. Install:
• Washer "1"
• Torque limiter "2"
• Washer "3"
Apply the engine oil to the shaft and
washers.
YAMAHA Bond No. 1215
(ThreeBond® No. 1215):
90890-85505
Nut (rotor):
65 Nm (6.5 m•kg, 47
ft•lb)
Sheave holder:
YS-1880-A/90890-
01701
Bolt [crankcase cover
(left)]:
10 Nm (1.0 m•kg, 7.2
ft•lb)

5-53
ENGINE REMOVAL
ENGINE REMOVAL
REMOVING THE ENGINE
Order Part name Q'ty Remarks
Hold the machine by placing the suitable stand
under the frame.Refer to "HANDLING NOTE".
Drain the engine oil.Refer to "CHANGING THE ENGINE OIL"
section in the CHAPTER 3.
Seat and fuel tank Refer to "REMOVING THE SEAT, FUEL
TANK AND SIDE COVERS" section in the
CHAPTER 3.
Radiator Refer to "RADIATOR" section.
Exhaust pipe and silencer Refer to "REMOVING THE EXHAUST PIPE
AND SILENCER" section in the CHAPTER 3.
Air cut-off valve assembly Refer to "AIR INDUCTION SYSTEM" section.
Clutch cable and guide Disconnect at the engine side.
Shift pedalRefer to "AC MAGNETO AND STARTER
CLUTCH" section.
Rear shock absorberRefer to "REAR SHOCK ABSORBER" sec-
tion in the CHAPTER 6.
Carburetor Refer to "CARBURETOR" section.
Cylinder head breather hose Refer to "CAMSHAFTS" section.
Oil hose and oil tank breather hose Refer to "OIL PUMP" section.

5-54
ENGINE REMOVAL
Ignition coil
Disconnect the AC magneto lead.
Disconnect the starter motor lead.Refer to "ELECTRIC STARTING SYSTEM"
section in the CHAPTER 7.
Negative battery lead Disconnect at the engine side.
1 Engine guard 1
2 Neutral switch 1
3 Drive chain sprocket cover 1
4 Nut (drive sprocket) 1 Refer to removal section.
5 Lock washer 1 Refer to removal section.
6 Drive sprocket 1 Refer to removal section.
7Clip 1
8 Bolt (brake pedal) 1
9 Brake pedal 1
10 Upper engine bracket 2
11 Lower engine bracket 2
12 Engine mounting bolt 3
13 Pivot shaft 1 Refer to removal section.
14 Engine 1 Refer to removal section. Order Part name Q'ty Remarks

5-58
CRANKCASE AND CRANKSHAFT
9 Left crankcase 1 Refer to removal section.
10 Oil strainer 1
11 Balancer shaft 1 Refer to removal section.
12 Crankshaft 1 Refer to removal section. Order Part name Q'ty Remarks

5-59
CRANKCASE AND CRANKSHAFT
REMOVING THE CRANKCASE BEARING
Order Part name Q'ty Remarks
TransmissionRefer to "TRANSMISSION, SHIFT CAM AND
SHIFT FORK" section.
Shift cam and shift fork Refer to "TRANSMISSION, SHIFT CAM AND
SHIFT FORK" section.
1 Oil seal 3
2 Bearing 10 Refer to removal section.

5-60
CRANKCASE AND CRANKSHAFT
DISASSEMBLING THE
CRANKCASE
1. Separate:
• Right crankcase
• Left crankcase
Separation steps:
a. Remove the crankcase bolts,
hose guide and clutch cable hold-
er.
Loosen each bolt 1/4 of a turn at a
time and after all the bolts are loos-
ened, remove them.
b. Remove the right crankcase.
• Place the crankcase with its left
side downward and split it by insert-
ing a screwdriver tip into the split-
ting slit "a" in the crankcase.
• Lift the right crankcase horizontally
while lightly patting the case split-
ting slit and engine mounting boss
using a soft hammer, and leave the
crankshaft and transmission with
the left crankcase.
Use soft hammer to tap on the
case half. Tap only on reinforced
portions of case. Do not tap on
gasket mating surface. Work slow-
ly and carefully. Make sure the
case halves separate evenly. If the
cases do not separate, check for a
remaining case bolt or fitting. Do
not force.
c. Remove the dowel pins and O-
ring.
REMOVING THE BALANCER
SHAFT
1. Remove:
• Balancer shaft "1"
Remove the balancer shaft with its
flat side "a" facing the crankshaft.
REMOVING THE CRANKSHAFT
1. Remove:
• Crankshaft "1"
Use the crankcase separating
tool "2".
Install the crankcase separating tool
as shown.
Do not use a hammer to drive out
the crankshaft.
REMOVING THE CRANKCASE
BEARING
1. Remove:
•Bearing "1"
• Remove the bearing from the
crankcase by pressing its inner
race.
• Do not use the removed bearing.
CHECKING THE TIMING CHAIN
AND TIMING CHAIN GUIDE
1. Inspect:
• Timing chain
Cracks/stiff→Replace the timing
chain and camshaft sprocket as a
set.
2. Inspect:
• Timing chain guide
Wear/damage→Replace.
CHECKING THE CRANKCASE
1. Inspect:
• Contacting surface "a"
Scratches→Replace.
• Engine mounting boss "b", crank-
case
Cracks/damage→Replace.
2. Inspect:
• Bearing
Rotate inner race with a finger.
Rough spot/seizure→Replace.
3. Inspect:
• Oil seal
Damage→Replace.
Crankcase separating
tool:
YU-A9642/90890-04152

5-61
CRANKCASE AND CRANKSHAFT
CHECKING THE CRANKSHAFT
1. Measure:
• Runout limit "a"
• Small end free play limit "b"
• Connecting rod big end side
clearance "c"
• Crank width "d"
Out of specification→Replace.
Use the dial gauge and a thick-
ness gauge.
CHECKING THE OIL STRAINER
1. Inspect:
• Oil strainer
Damage→Replace.INSTALLING THE CRANKCASE
BEARING
1. Install:
•Bearing
• Bearing stopper
• Bolt (bearing stopper)
• Screw (bearing stopper)
• Screw [bearing stopper (crank-
shaft)] "1"
To left and right crankcase.
• Install the bearing by pressing its
outer race parallel.
• To prevent the screw [bearing stop-
per (crankshaft)] from becoming
loose, crush the screw head periph-
ery "a" into the concave "b" using a
punch etc. In so doing, take care
not to damage the screwdriver re-
ceiving hole in the screw head.
INSTALLING THE CRANKSHAFT
1. Install:
• Crankshaft "1"
Use the crankshaft installing tool
"2", "3", "4" and "5".
• Hold the connecting rod at top dead
center with one hand while turning
the nut of the installing tool with the
other. Operate the installing tool un-
til the crankshaft bottoms against
the bearing.
• Before installing the crankshaft,
clean the contacting surface of
crankcase.
Do not use a hammer to drive in
the crankshaft.
A. For USA and CDN
B. Except for USA and CDN
2. Check:
• Shifter operation
• Transmission operation
Unsmooth operation→Repair.
3. Install:
• Oil strainer "1"
• Bolt (oil strainer) "2" Dial gauge and stand:
YU-3097/90890-01252
Standard
Runout
limit:0.03 mm
(0.0012 in)0.05 mm
(0.002 in)
Small
end
free
play:0.4–1.0 mm
(0.016–0.039
in)2.0 mm
(0.08 in)
Side
clear-
ance:0.15–0.45
mm (0.0059–
0.0177 in)0.50 mm
(0.02 in)
Crack
width:61.95–62.00
mm (2.439–
2.441 in)—
Bolt (bearing stopper):
10 Nm (1.0 m•kg, 7.2
ft•lb)
Screw (bearing stopper):
10 Nm (1.0 m•kg, 7.2
ft•lb)
Screw [bearing stopper
(crankshaft)]:
14 Nm (1.4 m•kg, 1.0
ft•lb)
Crankshaft installing pot
"2":
YU-90050/90890-01274
Crankshaft installing bolt
"3":
YU-90050/90890-01275
Adapter (M12) "4":
YU-90063/90890-01278
Spacer (crankshaft in-
staller) "5":
YM-91044/90890-04081
Bolt (oil strainer):
10 Nm (1.0 m•kg, 7.2
ft•lb)