Yamaha Wr 450 F Owners Manual

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ENGAC MAGNETO AND STARTER CLUTCH
EC4L3000
REMOVAL POINTS
Rotor
1. Remove:
Nut (rotor) 1 
Plain washer
2. Remove:
Rotor 1 
Use the rotor puller 2.
Rotor puller:
YM-04141/90890-04141
EC4L4000
INSPECTION
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.
EC4L4200
Woodruff key
1. Inspect:
Woodruff key 1 
Damage → Replace. 
						

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ENGAC MAGNETO AND STARTER CLUTCH
Starter clutch
1. Check:
Starter clutch
Damage/wear → Replace.
2. Check:
Idle gear
Idle gear shaft
Starter clutch gear
Pitting/burrs/chips/roughness/wear →
Replace the defective parts.
3. Check:
Starter clutch operation
Install the starter clutch drive gear 1 onto
the starter clutch 2 and hold the starter
clutch.
When turning the starter clutch drive gear
counterclockwise ı, 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.
When turning the starter clutch drive gear
clockwise Å, it should turn freely.
If the starter clutch drive gear does not
turn freely, the starter clutch is faulty and
must be replaced.
EC4L5000
ASSEMBLY AND INSTALLATION
AC magneto and starter clutch
1. Install:
Stator 1 
Bolt (stator) 2 
Pick-up coil 3 
Bolt (pick-up coil) 4 
NOTE:
Pass the AC magneto lead 5 under the pick-
up coil.
T R..7 Nm (0.7 m · kg, 5.1 ft · lb)
T R..10 Nm (1.0 m · kg, 7.2 ft · lb) 
						

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ENGAC MAGNETO AND STARTER CLUTCH
2. Install:
Holder 1 
Bolt 2 
NOTE:
Pass the pick-up coil lead 3 and AC mag-
neto lead 4 under the holder as shown.
Take care not to catch the AC magneto lead
between crankcase cover ribs.
Apply the sealant to the grommet of the AC
magneto lead.
Quick gasket:
ACC-QUICK-GS-KT
YAMAHA Bond No. 1215:
90890-85505
T R..7 Nm (0.7 m · kg, 5.1 ft · lb)
3. Install:
Plain washer 1 
Bearing 2 
Starter clutch drive gear 3 
Starter clutch 4 
NOTE:
Apply the engine oil on the plain washer, bear-
ing and starter clutch drive gear inner circum-
ference.
4. Install:
Woodruff key 1 
Rotor 2 
NOTE:
Clean the tapered portions of the crankshaft
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.
c
2 1 1
ba 
						

							 
4 - 81
ENG
 
5. Install: 
 
Bolt (starter clutch)   
1  
  
 
Plain washer (rotor) 
 
Nut (rotor)   
2  
 
NOTE:
 
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).
6. Install: 
 
Shaft   
1  
  
 
Bearing   
2  
  
 
Idle gear 2   
3  
 
NOTE:
 
Apply the engine oil on the shaft, bearing and 
idle gear inner circumference.
T R..16 Nm (1.6 m · kg, 11 ft · lb)
T R..65 Nm (6.5 m · kg, 47 ft · lb)
 
7. Install: 
 
Dowel pin 
 
Gasket [crankcase cover (left)]  
 
Crankcase cover (left)   
1  
  
 
Bolt [crankcase cover (left)] 
NOTE:
 
Tighten the bolts in stage, using a crisscross 
pattern.
New
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
 
8. Install: 
 
Shaft   
1  
  
 
Bearing   
2  
  
 
Idle gear 1   
3  
 
NOTE:
 
Apply the engine oil on the shaft, bearing and 
idle gear inner circumference. 
9. Install: 
 
Cover (idle gear 1)   
1  
  
 
Bolt   
2  
 
NOTE:
 
Install the cover (idle gear 1) with its mark   
a 
facing upward.
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
 
AC MAGNETO AND STARTER CLUTCH 
						

							 
4 - 82
ENG
 
10. Install: 
 
Engine guard   
1  
  
 
Clamp   
2  
  
 
Bolt [engine guard (front)]  
3  
  
 
Bolt [engine guard (rear)]  
4  
  
 
Cylinder head breather hose  
5  
 
T R..34 Nm (3.4 m · kg, 24 ft · lb)
T R..23 Nm (2.3 m · kg, 17 ft · lb)
 
11. Connect: 
 
AC magneto lead
Refer to “CABLE ROUTING DIA-
GRAM” section in the CHAPTER 2. 
12. Install: 
 
Shift pedal  
1 
  
 
Bolt (shift pedal)
NOTE:
 
When installing the shift pedal onto the shift
shaft, be sure that the center of the shift pedal
is about 1 mm (0.04 in)  
a 
 above the top of the 
footrest.
T R..12 Nm (1.2 m · kg, 8.7 ft · lb)
 
AC MAGNETO AND STARTER CLUTCH 
						

							 
4 - 83
ENG
 
ENGINE REMOVAL 
EC4M0000 
ENGINE REMOVAL 
Extent of removal Order Part name Q’ty Remarks 
ENGINE REMOVAL 
Preparation for removal Hold the machine by placing the 
suitable stand under the frame.
WARNING
 
Support the machine securely so there is no 
danger of it falling over. 
Drain the engine oil Refer to “ENGINE OIL REPLACEMENT” 
section in the CHAPTER 3.
Seat and fuel tank Refer to “SEAT, FUEL TANK AND SIDE 
COVERS” section.
Carburetor Refer to “CARBURETOR” section.
Exhaust pipe and silencer Refer to “EXHAUST PIPE AND 
SILENCER” section.
Clutch cable and guide Disconnect at the engine side.
Radiator Refer to “RADIATOR” section.
Shift pedal Refer to “AC MAGNETO AND 
STARTER CLUTCH” section.
Cylinder head breather hose and 
oil tank breather hoseRefer to “CAMSHAFTS” section.
Ignition coil
Disconnect the AC magneto lead. 
						

							 
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ENG
 
ENGINE REMOVAL 
Extent of removal: 
1 
 Engine removal
Extent of removal Order Part name Q’ty Remarks
Crankcase cover (left) Refer to “AC MAGNETO AND 
STARTER CLUTCH” section for remov-
ing the starter motor lead.
Disconnect the starter motor 
lead.Refer to “ELECTRIC STARTING SYS-
TEM” section in the CHAPTER 6.
Negative battery lead Disconnect at the starter motor side.
1 Engine skid plate (front) 1
2 Neutral switch 1
3 Oil hose 2
4 Chain cover 1
5 Nut (drive sprocket) 1
Refer to “REMOVAL POINTS”. 6 Lock washer 1
7 Drive sprocket 1
8 Clip 1
9 Bolt (brake pedal) 1
10 Brake pedal 1
1 
						

							 
4 - 85
ENG
 
ENGINE REMOVAL 
Extent of removal Order Part name Q’ty Remarks
11 Engine upper bracket (right) 1
12 Engine upper bracket (left) 1
13 Engine lower bracket 2
14 Engine mounting bolt 3
15 Pivot shaft 1
Refer to “REMOVAL POINTS”.
16Engine
1
1 
						

							 
4 - 86
ENG
 
ENGINE REMOVAL 
EC4M3000 
REMOVAL POINTS 
EC4F3100 
Drive sprocket 
1. Remove: 
 
Nut (drive sprocket) 1 
Lock washer 2 
NOTE:
Straighten the lock washer tab.
Loosen the nut while applying the rear brake.
2. Remove:
Drive sprocket 1 
Drive chain 2 
NOTE:
Remove the drive sprocket together with the
drive chain.
EC4M3301
Engine removal
1. Remove:
Pivot shaft 1 
NOTE:
If the pivot shaft is pulled all the way out, the
swingarm will come loose. If possible, insert a
shaft of similar diameter into the other side of
the swingarm to support it.
2. Remove:
Engine 1 
From right side.
NOTE:
Make sure that the couplers, hoses and cables
are disconnected.
1 
						

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ENGENGINE REMOVAL
EC4M5000
ASSEMBLY AND INSTALLATION
Engine installation
1. Install:
Engine 1 
Install the engine from right side.
Pivot shaft 2 
Engine mounting bolt (lower) 3 
Engine lower bracket 4 
Bolt (engine bracket) 5 
Engine mounting bolt (front) 6 
Engine upper bracket (right) 7 
Engine upper bracket (left) 8 
Bolt (engine bracket) 9 
Engine mounting bolt (upper) 0 
Bolt (engine guard) A 
Engine skid plate (front) B 
Bolt (engine skid plate) C 
NOTE:
Apply the molybdenum disulfide grease on the
pivot shaft.
T R..85 Nm (8.5 m · kg, 61 ft · lb)
T R..69 Nm (6.9 m · kg, 50 ft · lb)
T R..34 Nm (3.4 m · kg, 24 ft · lb)
T R..69 Nm (6.9 m · kg, 50 ft · lb)
T R..55 Nm (5.5 m · kg, 40 ft · lb)
T R..55 Nm (5.5 m · kg, 40 ft · lb)
T R..23 Nm (2.3 m · kg, 17 ft · lb)
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
EC4M5211
Brake pedal
1. Install:
Spring
Brake pedal 1 
O-ring 2 
Bolt (brake pedal) 3 
Clip 4 
NOTE:
Apply the lithium soap base grease on the
bolt, O-rings and brake pedal bracket.
Install the clip with its stopper portion a fac-
ing inward.
New
T R..26 Nm (2.6 m · kg, 19 ft · lb)