Yamaha YFM45FAR, YFM450FAR. Service Manual

3 - 55

CHK

ADJ

CHECKING THE BATTERY

EB305000

ELECTRICAL

CHECKING THE BATTERY

NOTE:

Since the MF battery is a sealed type battery, it
is not possible to measure the specific gravity
of the electrolyte in order to check the charge
state of the battery. Therefore, the charge of
the battery has to be checked by measuring
the voltage at the battery terminals.

CAUTION:

CHARGING METHOD

●

This is a sealed type battery. Never
remove the sealing caps. If the sealing
caps have been removed, the balance will
not be maintained and battery
performance will deteriorate.

●

Charging time, charging current and
charging voltage for the MF battery are
different from those of general type
batteries. The MF battery should be
charged as explained in “CHARGING
METHOD”. If the battery is overcharged,
the electrolyte level will drop
considerably. Therefore, take special care
when charging the battery.

WARNING

Battery electrolyte is dangerous; it
contains sulfuric acid which is poisonous
and highly caustic.
Always follow these preventive measures:

●

Avoid bodily contact with electrolyte as it
can cause severe burns or permanent eye
injury.

●

Wear protective eye gear when handling
or working near batteries.

Antidote (EXTERNAL):

●

SKIN - Wash with water.

●

EYES - Flush with water for 15 minutes
and get immediate medical attention.

Antidote (INTERNAL):

●

Drink large quantities of water or milk
followed with milk of magnesia, beaten
egg or vegetable oil. Get immediate
medical attention.

3 - 56

CHK

ADJ

Batteries generate explosive hydrogen gas.
Always follow these preventive measures:

●

Charge batteries in a well-ventilated area.

●

Keep batteries away from fire, sparks or
open flames (e.g., welding equipment,
lighted cigarettes, etc.)

●

DO NOT SMOKE when charging or
handling batteries.

KEEP BATTERIES AND ELECTROLYTE
OUT OF REACH OF CHILDREN.

1.Remove:

●

Seat

●

Battery holding bracket

●

Battery lead cover
Refer to “SEAT, CARRIERS, FENDERS
AND FUEL TANK”.

2.Disconnect:

●

Battery leads

CAUTION:

First disconnect the negative lead

, then

disconnect the positive lead

3.Remove:

●

Battery

4.Check:

●

Battery condition

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

Battery condition checking steps:

●

Connect a digital voltmeter to the battery
terminals.

NOTE:

The charge state of an MF battery can be
checked by measuring the open-circuit voltage
(i.e. the voltage when the positive terminal is
disconnected).

Tester (+) lead

→

battery (+) terminal

Tester (–) lead

→

battery (–) terminal

CHECKING THE BATTERY

3 - 57

CHK

ADJ

CHECKING THE BATTERY

●

Check the condition of the battery using the
following charts.

Example:

●

Open-circuit voltage = 12.0 V

●

Charging time = 6.5 hours

●

Charge condition of the battery = 20 ~ 30%

●

Charging method for MF batteries

CAUTION:

●

If it is impossible to set the standard
charging current, be careful not to
overcharge.

●

When charging the battery, be sure to
remove it from the motorcycle. (If
charging has to be done with the battery
mounted on the motorcycle, be sure to
disconnect the wire at the negative
terminal.)

●

Never remove the sealing caps of an MF
battery.

●

Make sure that the charging clips are in
full contact with the terminal and that they
are not shorted together. (A corroded clip
on the charger may cause the battery to
generate heat in the contact area. A weak
clip spring may cause sparks.)

●

Before removing the clips from the
battery terminals, be sure to turn off the
charger’s power switch.

●

The open-circuit voltage variation for the
MF battery, after charging, is shown
below. As shown in the figure, the open-
circuit voltage stabilizes about 30
minutes after charging has been
completed. Therefore, wait 30 minutes
after charging is completed before
measuring the open-circuit voltage.

Open-circuit

voltage

Charging time

12.8 V or higher

No charging is

necessary.

3 - 58

CHK

ADJ

CHECKING THE BATTERY

Charging method using a variable voltage charger

Measure the open-circuit
voltage prior to charging.

Connect a charger and
ammeter to the battery and
start charging.

Is the amperage higher
than the standard charging
amperage written on the
battery?

YES

Charger

Ammeter

Adjust the voltage to obtain the
standard charging amperage.

Set the timer to the charging
time determined by the open-
circuit voltage.
Refer to “CHECKING THE
BATTERY”.

Adjust the charging voltage to
20 ~ 25 V.

Monitor the amperage for 3 ~
5 minutes. Is the standard
charging amperage exceeded?

YES

If the amperage does not
exceed the standard charging
amperage after 5 minutes,
replace the battery.

If the required charging time exceeds 5 hours, it is advisable to check the
charging amperage after 5 hours. If there is any change in the amperage,
readjust the voltage to obtain the standard charging amperage.

Leave the battery unused for more than 30 minutes before measuring its
open-circuit voltage.
12.8 V

→

Charging is complete.

12.0 ~ 12.7 V

→

Recharging is required.

Under 12.0 V

→

Replace the battery.

Leave the battery unused for
more than 30 minutes before
measuring its open-circuit voltage.

Set the charging voltage to
16 ~ 17 V. (If the charging
voltage is lower, charging will
be insufficient, if it is higher,
the battery will be over-
charged.)

NOTE:

3 - 59

CHK

ADJ

CHECKING THE BATTERY

Charging method using a constant voltage charger

Measure the open-circuit
voltage prior to charging.

Connect a charger and
ammeter to the battery and
start charging.

YES

Is the amperage higher
than the standard charging
amperage written on the
battery?

Charge the battery until the charging
voltage reaches 15 V.

Leave the battery unused for more than 30
minutes before measuring its open-circuit
voltage.
12.8 V

→

Charging is complete.

12.0 ~ 12.7 V

→

Recharging is required.

Under 12.0 V

→

Replace the battery.

This type of battery charger cannot
charge an MF battery. A variable
voltage charger is recommended.

Leave the battery unused for
more than 30 minutes before
measuring its open-circuit voltage.

NOTE:

Set the charging time to a
maximum of 20 hours.

NOTE:

Constant amperage chargers are
not suitable for charging MF
batteries.

CAUTION:

Charger

Ammeter

Voltmeter

3 - 60

CHK

ADJ

CHECKING THE BATTERY/

CHECKING THE FUSE

5.Check:

●

Battery terminals
Dirty

→

Clean with a wire brush.

Poor connection

→

Correct.

NOTE:

After cleaning the terminals, apply a light coat
of grease.

6.Install:

●

Battery

7.Connect:

●

Battery leads

CAUTION:

First, connect the positive lead

, then

connect the negative lead

8.Install:

●

Battery lead cover

●

Battery holding bracket

●

Seat
Refer to “SEAT, CARRIERS, FENDERS
AND FUEL TANK”.

CHECKING THE FUSE

CAUTION:

Always turn off the main switch when
checking or replacing a fuse. Otherwise, a
short circuit may occur.

1.Remove:

●

Seat
Refer to “SEAT, CARRIERS, FENDERS
AND FUEL TANK”.

2.Check:

●

Fuses

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

Checking steps:

●

Connect the pocket tester to the fuse and
check it for continuity.

3 - 61

CHK

ADJ

CHECKING THE FUSE

NOTE:

Set the tester to the “

Ω ×

1” position.

●

If the tester indicates

∞

, replace the fuse.

*****************************************************
3.Replace:

●

Blown fuse

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

Replacement steps:

●

Turn off the ignition.

●

Install a new fuse of the proper amperage.

●

Turn on switches to verify operation of the
related electrical devices.

●

If the fuse immediately blows again, check
the electrical circuit.

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

WARNING

Never use a fuse with a rating other than
that specified. Never use other materials in
place of a fuse. An improper fuse may cause
extensive damage to the electrical system, a
malfunction of the lighting and ignition
systems and could possibly cause a fire.

Pocket tester:

P/N. YU-03112, 90890-03112

Description

Current rating

Quantity

Main

30 A

Headlight

15 A

Ignition

10 A

Terminal
(Auxiliary
DC jack)

10 A

4WD (Four-
wheel drive)

3 A

Signaling
system fuse

10 A

Backup fuse
(odometer)

10 A

Reserve

30 A

Reserve

15 A

Reserve

10 A

Reserve

3 A

3 - 62

CHK

ADJ

CHECKING THE FUSE/ADJUSTING THE HEADLIGHT

BEAM/CHANGING THE HEADLIGHT BULB

4.Install:

●

Seat
Refer to “SEAT, CARRIERS, FENDERS
AND FUEL TANK”.

ADJUSTING THE HEADLIGHT BEAM

1.Adjust:

●

Headlight beam (vertically)
Turn the adjuster

in or out.

Turning in

Headlight beam raised.

Turning out Headlight beam lowered.

CHANGING THE HEADLIGHT BULB

1.Remove:

●

Cover

2.Remove:

●

Bulb holder

●

Bulb

NOTE:

Turn the bulb holder counterclockwise and
remove the defective bulb.

WARNING

Keep flammable products and your hands
away from the bulb while it is on, since it
will be hot. Do not touch the bulb until it
cools down.

3 - 63

CHK

ADJ

CHANGING THE HEADLIGHT BULB

3.Install:

●

Bulb
Secure the new bulb with the headlight unit.

CAUTION:

Avoid touching the glass part of the bulb.
Keep it free from oil; otherwise, the
transparency of the glass, life of the bulb,
and luminous flux will be adversely
affected. If oil gets on the bulb, thoroughly
clean it with a cloth moistened with alcohol
or lacquer thinner.

4.Install:

●

Bulb holder

●

Cover

New

ENG

CHAPTER 4.

ENGINE

ENGINE REMOVAL

..................................................................................... 4-1

AIR DUCTS, MUFFLER AND EXHAUST PIPE  .................................... 4-1
SELECT LEVER UNIT AND COOLANT RESERVOIR  ......................... 4-3
HOSES AND LEADS  ............................................................................ 4-4
ENGINE MOUNTING BOLTS  ............................................................... 4-5
INSTALLING THE ENGINE  .................................................................. 4-7

CYLINDER HEAD

......................................................................................... 4-8

REMOVING THE CYLINDER HEAD  .................................................. 4-10
CHECKING THE TAPPET COVER  .................................................... 4-11
CHECKING THE TIMING CHAIN TENSIONER  ................................. 4-11
CHECKING THE CAMSHAFT SPROCKET ........................................ 4-11
CHECKING THE CYLINDER HEAD  ................................................... 4-12
INSTALLING THE CYLINDER HEAD  ................................................. 4-13

CAMSHAFT, ROCKER ARMS AND VALVES

........................................... 4-16

REMOVING THE CAMSHAFT AND ROCKER ARM  .......................... 4-18
REMOVING THE VALVE AND VALVE SPRING  ................................ 4-18
CHECKING THE CAMSHAFT  ............................................................ 4-19
CHECKING THE ROCKER ARM AND CAMSHAFT  .......................... 4-19
CHECKING THE VALVE AND VALVE SPRING ................................. 4-21
INSTALLING THE VALVE AND VALVE SPRING ............................... 4-25
INSTALLING THE CAMSHAFT AND ROCKER ARM  ........................ 4-26

CYLINDER AND PISTON

........................................................................... 4-27

REMOVING THE PISTON  .................................................................. 4-28
CHECKING THE TIMING CHAIN GUIDE  ........................................... 4-28
CHECKING THE CYLINDER AND PISTON  ....................................... 4-28
CHECKING THE PISTON RING ......................................................... 4-30
CHECKING THE PISTON PIN ............................................................ 4-31
INSTALLING THE PISTON ................................................................. 4-32
INSTALLING THE CYLINDER  ............................................................ 4-33

RECOIL STARTER AND A.C. MAGNETO

............................................... 4-34

REMOVING THE A.C. MAGNETO  ..................................................... 4-37
DISASSEMBLING THE RECOIL STARTER ....................................... 4-37
CHECKING THE CDI MAGNETO ....................................................... 4-37
CHECKING THE STARTER CLUTCH ................................................ 4-38
CHECKING THE STARTER PULLEY ................................................. 4-39
CHECKING THE RECOIL STARTER  ................................................. 4-39
ASSEMBLING THE RECOIL STARTER ............................................. 4-39
INSTALLING THE A.C. MAGNETO  .................................................... 4-40

ENG

PRIMARY AND SECONDARY SHEAVES

................................................. 4-42

PRIMARY SLIDING SHEAVE  ............................................................. 4-44
SECONDARY SHEAVE  ...................................................................... 4-45
REMOVING THE PRIMARY AND SECONDARY SHEAVES  ............. 4-46
DISASSEMBLING THE SECONDARY SHEAVE  ............................... 4-46
CHECKING THE PRIMARY SHEAVE  ................................................ 4-47
CHECKING THE SECONDARY SHEAVE .......................................... 4-47
ASSEMBLING THE PRIMARY SHEAVE ............................................ 4-48
ASSEMBLING THE SECONDARY SHEAVE  ..................................... 4-48
INSTALLING THE PRIMARY AND SECONDARY SHEAVES  ........... 4-50

CLUTCH

..................................................................................................... 4-51

REMOVING THE CLUTCH ................................................................. 4-53
CHECKING THE CLUTCH .................................................................. 4-53
INSTALLING THE CLUTCH ................................................................ 4-54

CRANKCASE

............................................................................................. 4-56

STARTER MOTOR, TIMING CHAIN AND OIL FILTER ...................... 4-56
CRANKCASE ...................................................................................... 4-58
CRANKCASE BEARING ..................................................................... 4-59
REMOVING THE OIL PUMP DRIVE GEAR  ....................................... 4-60
SEPARATING THE CRANKCASE ...................................................... 4-60
CHECKING THE TIMING CHAIN AND GUIDE  .................................. 4-61
CHECKING THE OIL STRAINER AND OIL DELIVERY PIPE  ............ 4-61
CHECKING THE CRANKCASE .......................................................... 4-62
CHECKING THE BEARINGS .............................................................. 4-62
ASSEMBLING THE CRANKCASE  ..................................................... 4-62
INSTALLING THE SHIFT LEVER  ....................................................... 4-63
INSTALLING THE OIL PUMP DRIVE GEAR ...................................... 4-64

CRANKSHAFT AND OIL PUMP

................................................................ 4-65

OIL PUMP  ........................................................................................... 4-66
REMOVING THE CRANKSHAFT  ....................................................... 4-67
CHECKING THE OIL PUMP  ............................................................... 4-67
CHECKING THE CRANKSHAFT ........................................................ 4-68
INSTALLING THE CRANKSHAFT AND BALANCER ......................... 4-69

TRANSMISSION

......................................................................................... 4-70

CHECKING THE SHIFT FORK ........................................................... 4-72
CHECKING THE SHIFT CAM ............................................................. 4-72
CHECKING THE TRANSMISSION ..................................................... 4-73
CHECKING THE SECONDARY SHAFT AND DRIVEN SPROCKET . 4-73
CHECKING THE CHAIN ..................................................................... 4-74
CHECKING THE STOPPER LEVER AND STOPPER WHEEL .......... 4-74
INSTALLING THE TRANSMISSION ................................................... 4-74

ENG

MIDDLE GEAR

........................................................................................... 4-76

MIDDLE DRIVE SHAFT  ...................................................................... 4-76
MIDDLE DRIVEN SHAFT  ................................................................... 4-77
REMOVING THE MIDDLE DRIVE SHAFT  ......................................... 4-79
REMOVING THE MIDDLE DRIVEN SHAFT ....................................... 4-79
CHECKING THE PINION GEAR ......................................................... 4-81
SELECTING THE MIDDLE DRIVE AND DRIVEN GEAR SHIM  ......... 4-82
INSTALLING THE MIDDLE DRIVEN SHAFT  ..................................... 4-85
INSTALLING THE MIDDLE DRIVE SHAFT ........................................ 4-87
MEASURING THE MIDDLE GEAR BACKLASH  ................................ 4-87

4 - 1

ENG

ENGINE REMOVAL

ENGINE

ENGINE REMOVAL

AIR DUCTS, MUFFLER AND EXHAUST PIPE

Order

Job name/Part name

Q’ty

Remarks

Removing the air ducts, muffler and
exhaust pipe

Remove the parts in the order below.

Engine oil

Drain.
Refer to “CHANGING THE ENGINE OIL”
in CHAPTER 3.

Front and rear fender/footrest boards

Refer to “SEAT, CARRIERS, FENDERS
AND FUEL TANK” in CHAPTER 3.

Fuel tank/rubber cover
Coolant Drain.

Refer to “CHANGING THE COOLANT” in
CHAPTER 3.

Carburetor assembly

Refer to “CARBURETOR” in CHAPTER 6.

Air duct assembly 1

Muffler

Exhaust pipe stay 1

Exhaust pipe/gasket

1/1

Air duct assembly 2

Yamaha YFM45FAR, YFM450FAR. Service Manual - part 8