Yamaha YFM45FAR, YFM450FAR. Service Manual

4 - 66

ENG

CRANKSHAFT AND OIL PUMP

OIL PUMP

Order

Job name/Part name

Q’ty

Remarks

Disassembling the oil pump

Remove the parts in the order below.

Rotor cover

Shaft

Inner rotor

Outer rotor

Oil pump housing

For assembly, reverse the disassembly
procedure.

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ENG

CRANKSHAFT AND OIL PUMP

REMOVING THE CRANKSHAFT

1.Remove:

●

Crankshaft seal

NOTE:

Mark a note of the position of each crankshaft
seal so that they can be installed in the correct
place and in the correct direction.

2.Remove:

●

Crankshaft
Use a crankcase separating tool

Crankcase separating tool:

P/N. YU-01135-A, 90890-01135

CHECKING THE OIL PUMP

1.Check:

●

Oil pump driven gear

●

Oil pump housing

●

Rotor cover
Cracks/wear/damage

→

Replace.

2.Measure:

●

Tip clearance

(between the inner rotor

and the outer

rotor

)

●

Side clearance

(between the outer rotor

and the pump

housing

)

Out of specification

→

Replace the oil pump.

Tip clearance

0.15 mm (0.006 in)
<Limit>: 0.20 mm (0.008 in)

Side clearance

0.04 ~ 0.09 mm (0.002 ~ 0.004 in)

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ENG

CRANKSHAFT AND OIL PUMP

3.Check:

●

Oil pump operation
Unsmooth

→

Repeat steps #1 and #2 or

replace the defective parts.

CHECKING THE CRANKSHAFT

1.Measure:

●

Crank width

Out of specification

→

Replace the

crankshaft.

●

Side clearance

Out of specification

→

Replace the

crankshaft.

●

Runout

Out of specification

→

Replace the

crankshaft.

*****************************************************

Crankshaft reassembling point:

The crankshaft

and the crank pin

oil

passages must be properly interconnected
with a tolerance of less than 1 mm (0.04 in).

*****************************************************

CAUTION:

The buffer boss and woodruff key should
be replaced when removed from the
crankshaft.

Crank width:

62.95 ~ 63.00 mm
(2.4783 ~ 2.4803 in)

Big end side clearance:

0.25 ~ 0.75 mm
(0.0098 ~ 0.0295 in)
<Limit>: 1.00 mm (0.0394 in)

Runout limit:

C1: 0.03 mm (0.0012 in)
C2: 0.03 mm (0.0012 in)

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ENG

CRANKSHAFT AND OIL PUMP

INSTALLING THE CRANKSHAFT AND
BALANCER

1.Install:

●

Crankshaft

NOTE:

Hold the connecting rod at the Top Dead
Center (T.D.C.) with one hand while turning
the nut of the installing tool with the other.
Operate the installing tool until the crankshaft
bottoms against the bearing.

CAUTION:

Apply engine oil to each bearing to protect
the crankshaft against scratches and to
make installation easier.

Crankshaft installer set

P/N. YU-90050

Buffer boss installer set

P/N. 90890-04088

Adapter #11

P/N. YM-33279

Spacer (crankshaft)

P/N. YM-90070-A, 90890-04060

2.Install:

●

Crankshaft seal

NOTE:

Install the crankshaft seals in the correct place
and in the correct direction.

3.Install:

●

Balancer

NOTE:

Align the punch marks

on the drive and

driven gear.

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ENG

TRANSMISSION

Order

Job name/Part name

Q’ty

Remarks

Removing the transmission

Remove the parts in the order below.

Crankcase separation

Refer to “CRANKCASE”.

Driven sprocket

Chain

Clutch dog 2

Shift fork “L”

Spring

Low wheel gear

Secondary shaft

Middle driven gear

Drive axle assembly

Guide bar

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ENG

TRANSMISSION

Order

Job name/Part name

Q’ty

Remarks

Shift fork “R”

Spring

Shift cam

Stopper wheel

Clutch dog 1

High wheel gear

Middle drive gear

Stopper lever

Spacer/O-ring

1/1

For installation, reverse the removal
procedure.

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ENG

TRANSMISSION

CHECKING THE SHIFT FORK

1.Check:

●

Shift fork cam follower

●

Shift fork pawl

Scoring/bends/wear/damage

→

Replace.

2.Check:

●

Guide bar
Roll the guide bar on a flat surface.
Bends

→

Replace.

WARNING

Do not attempt to straighten a bent guide
bar.

3.Check:

●

Shift fork movement
(on the guide bar)
Unsmooth operation

→

Replace the shift fork

and the guide bar.

4.Check:

●

Spring
Cracks/damage

→

Replace.

CHECKING THE SHIFT CAM

1.Check:

●

Shift cam grooves
Scratches/wear/damage

→

Replace.

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ENG

TRANSMISSION

CHECKING THE TRANSMISSION

1.Measure:

●

Axle runout
Use a centering device and a dial gauge.
Out of specification

→

Replace the bent axle.

Runout limit (drive axle):

0.06 mm (0.0024 in)

2.Check:

●

Gear teeth
Blue discoloration/pitting/wear

→

Replace.

●

Mated dogs
Rounded edges/cracks/missing portions

→

Replace.

3.Check:

●

Gear movement
Unsmooth

→

Repeat steps #1 and #2 or

replace the defective parts.

4.Check:

●

Circlip
Bends/looseness/damage

→

Replace.

CHECKING THE SECONDARY SHAFT AND
DRIVEN SPROCKET

1.Check:

●

Gear teeth
Blue discoloration/pitting/wear

→

Replace.

2.Check:

●

Gear movement
Unsmooth

→

Repeat steps #1 or replace the

defective parts.

3.Check:

●

Circlip

●

Bends/looseness/damage

→

Replace.

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ENG

TRANSMISSION

CHECKING THE CHAIN

1.Check:

●

Chain
Cracks/shift

→

Replace

the chain, secondary

shaft and driven sprocket as a set.

CHECKING THE STOPPER LEVER AND
STOPPER WHEEL

1.Check:

●

Stopper lever pawl

Bends/damage/wear

→

Replace

the stopper

lever and stopper wheel as a set.

●

Stopper wheel

Damage/wear

→

Replace

the stopper wheel

and stopper lever as a set.

●

Shaft

Bends/damage/wear

→

Replace.

INSTALLING THE TRANSMISSION

1.Install:

●

Shift cam

●

Washer

●

Spring (short)

●

Shift fork “R”

●

Drive axle assembly

●

Guide bar

●

Clutch dog 2

●

Spring (long)

●

Shift fork “L”

NOTE:

Install the shift fork with the “R” mark facing
towards the right side of the crankcase and the
shift fork with the “L” mark facing towards the
left side of the crankcase. Be sure that the shift
fork guide pin is properly seated in the shift
drum groove.

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ENG

MIDDLE GEAR

MIDDLE DRIVE SHAFT

Order

Job name/Part name

Q’ty

Remarks

Removing the middle drive shaft

Remove the parts in the order below.

Crankcase separation

Refer to “CRANKCASE”.

Transmission

Refer to “TRANSMISSION”.

Bearing housing assembly

Nut

Refer to “REMOVING/INSTALLING THE
MIDDLE DRIVE SHAFT”.

Middle drive pinion gear

Shim

Refer to “SELECTING THE MIDDLE
DRIVE AND DRIVEN GEAR SHIM”.

Middle drive shaft

Bearing retainer

For installation, reverse the removal
procedure.

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ENG

MIDDLE GEAR

MIDDLE DRIVEN SHAFT

Order

Job name/Part name

Q’ty

Remarks

Removing the middle driven shaft

Remove the parts in the order below.

Crankcase separation

Refer to “CRANKCASE”.

Circlip

Refer to “REMOVING/INSTALLING THE
MIDDLE DRIVEN SHAFT”.

Bearing

Universal joint

Universal joint yoke

Bearing housing/O-ring

1/1

Shim

Refer to “SELECTING THE MIDDLE
DRIVE AND DRIVEN GEAR SHIM”.

Middle drive pinion gear

Refer to “REMOVING/INSTALLING THE
MIDDLE DRIVEN SHAFT”.

Bearing retainer

Damper cam

Spring

Gear coupling

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ENG

MIDDLE GEAR

REMOVING THE MIDDLE DRIVE SHAFT

1.Straighten:

●

Punched portion of the nut (middle drive
pinion gear)

2.Loosen:

●

Nut (middle drive pinion gear)

NOTE:

Secure the middle drive shaft in the vise with a
clean rag.

3.Remove:

●

Nut (middle drive pinion gear)

●

Middle drive pinion gear

●

Shim(s)

REMOVING THE MIDDLE DRIVEN SHAFT

1.Remove:

●

Universal joint

*****************************************************

Removal steps:

●

Remove the circlips

●

Place the U-joint in a press.

●

With a suitable diameter pipe

beneath the

yoke

, press the bearing

into the pipe as

shown.

NOTE:

It may be necessary to lightly tap the yoke with
a punch.

●

Repeat the steps for the opposite bearing.

●

Remove the yoke.

NOTE:

It may be necessary to lightly tap the yoke with
a punch.

*****************************************************

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ENG

MIDDLE GEAR

2.Remove:

●

Nut

●

Washer

●

Universal joint yoke

NOTE:

Use the universal joint holder

to hold the

universal joint yoke.

3.Remove:

●

Bearing housing assembly

*****************************************************

Removal steps:

●

Clean the outside of the middle driven shaft.

●

Place the middle driven shaft onto a
hydraulic press.

CAUTION:

●

Never directly press the shaft end with a
hydraulic press, this will result in damage
to the shaft thread.

●

Install the suitable socket

on the shaft

end to protect the thread from damage.

●

Press the shaft end and remove the bearing
housing.

*****************************************************
4.Remove:

●

Bearing retainer

●

Bearing

*****************************************************

Removal steps:

●

Attach the folded rag

●

Secure the bearing housing edge in the vise.

●

Attach the bearing retainer wrench

CAUTION:

The middle driven shaft bearing retainer
has left-handed threads. To loosen the
retainer turn it clockwise.

●

Remove the bearing retainer and bearing.

*****************************************************

Universal joint holder:

P/N. YM-04062, 90890-04062

Bearing retainer wrench:

P/N. YM-04128, 90890-04128

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ENG

MIDDLE GEAR

5.Remove:

●

Front drive shaft coupling

●

Bearing retainer

●

Bearing

NOTE:

Attach the ring nut wrench

CAUTION:

The middle driven shaft bearing retainer
has left-handed threads. To loosen the
retainer turn it clockwise.

Ring nut wrench:

P/N. YM-38404, 90890-01430

6.Remove:

●

Middle drive shaft

(with bearing)

CHECKING THE PINION GEAR

1.Check:

●

Damper cam surfaces
Wear/scratches

→

Replace damper cam and

driven pinion gear as a set.

2.Check:

●

Damper spring
Damage/cracks

→

Replace.

3.Check:

●

Gear teeth (drive pinion gear)

●

Gear teeth (driven pinion gear)

Pitting/galling/wear

→

Replace.

Yamaha YFM45FAR, YFM450FAR. Service Manual - part 13