Yamaha YFM45FAR, YFM450FAR. Service Manual - part 25

10 - 3

TRBL

SHTG

FAULTY DRIVE TRAIN

FAULTY DRIVE TRAIN

The following conditions may indicate damaged shaft drive components:

NOTE:

Areas A, B, and C above may be extremely difficult to diagnose. The symptoms are quite subtle and
difficult to distinguish from normal machine operating noise. If there is reason to believe these
components are damaged, remove the components and check them.

Symptoms

Possible Causes

1.A pronounced hesitation or “jerky” movement

during acceleration, deceleration, or sustained
speed. (This must not be confused with
engine surging or transmission
characteristics.)

2.A  “rolling rumble” noticeable at low speed; a

high-pitched whine; a “clunk” from a shaft
drive component or area.

3.A locked-up condition of the shaft drive

mechanism, no power transmitted from the
engine to the front and/or rear wheels.

A.Bearing damage.

B.Improper gear lash.

C.Gear tooth damage.

D.Broken drive shaft.

E.Broken gear teeth.

F.Seizure due to lack of lubrication.

G.Small foreign objects lodged between the 

moving parts.

10 - 4

TRBL

SHTG

FAULTY GEAR SHIFTING/

FAULTY CLUTCH PERFORMANCE

FAULTY GEAR SHIFTING

HARD SHIFTING

Refer to “CLUTCH SLIPPING/DRAGGING-CLUTCH DRAGGING”.

SHIFT LEVER DOES NOT MOVE
Shift shaft

●

Bent shift shaft

Shift cam, shift fork

●

Groove jammed with impurities

●

Seized shift fork

●

Bent shift fork guide bar

Transmission

●

Seized transmission gear

●

Jammed impurities

●

Incorrectly assembled transmission

Shift guide

●

Broken shift guide

JUMPS OUT OF GEAR
Shift shaft

●

Improperly adjusted shift lever position

●

Worn shift shaft lever

●

Improperly returned stopper lever

Shift fork

●

Worn shift fork

Shift cam

●

Improper thrust play

●

Worn shift cam groove

Transmission 

●

Worn gear dog

FAULTY CLUTCH PERFORMANCE

ENGINE OPERATES BUT MACHINE WILL NOT MOVE
V-belt

●

Bent, damaged or worn V-belt

●

V-belt slips

Primary pulley cam and primary pulley slider

●

Damaged or worn primary pulley cam

●

Damaged or worn primary pulley slider

Transmission

●

Damaged transmission gears

CLUTCH SLIPPING
Clutch spring

●

Damaged, loose or worn clutch shoe spring

Clutch shoe

●

Damaged or worn clutch shoe

Primary sliding sheave

●

Seized primary sliding sheave

POOR STARTING PERFORMANCE
V-belt

●

V-belt slips

●

Oil or grease on the V-belt

Primary sliding sheave

●

Faulty operation

●

Worn pin groove

●

Worn pin

Clutch shoe

●

Bent, damaged or worn clutch shoe

10 - 5

TRBL

SHTG

FAULTY CLUTCH PERFORMANCE/

OVERHEATING/FAULTY BRAKE

POOR SPEED PERFORMANCE
V-belt

●

Oil or grease on the V-belt

Primary pulley weight

●

Faulty operation

●

Worn primary pulley weight

Primary fixed sheave

●

Worn primary fixed sheave

Primary sliding sheave

●

Worn primary sliding sheave

Secondary fixed sheave

●

Worn secondary fixed sheave

Secondary sliding sheave

●

Worn secondary sliding sheave

OVERHEATING

OVERHEATING
Ignition system

●

Improper spark plug gap

●

Improper spark plug heat range

●

Faulty CDI unit

Fuel system

●

Improper carburetor main jet
(improper setting)

●

Improper fuel level

●

Clogged air filter element

Compression system

●

Heavy carbon build-up

Engine oil

●

Improper oil level

●

Improper oil viscosity

●

Inferior oil quality

Cooling system

●

Low coolant level

●

Damaged or leaking radiator

●

Faulty radiator cap

●

Bent or damaged radiator fin

●

Damaged or faulty water pump

●

Thermostat stays closed

●

Clogged or damaged oil cooler

●

Damaged hose

●

Improperly connected hose

●

Damaged pipe

●

Improperly connected pipe

Brake

●

Brake drag

FAULTY BRAKE

POOR BRAKING EFFECT

●

Worn brake pads

●

Worn disc

●

Air in brake fluid

●

Leaking brake fluid

●

Faulty master cylinder kit cup

●

Faulty caliper kit seal

●

Loose union bolt

●

Broken brake hose and pipe

●

Oily or greasy disc/brake pads

●

Improper brake fluid level

10 - 6

TRBL

SHTG

SHOCK ABSORBER MALFUNCTION

MALFUNCTION

●

Bent or damaged damper rod

●

Damaged oil seal lip

●

Fatigued shock absorber spring

SHOCK ABSORBER MALFUNCTION/UNSTABLE

HANDLING/LIGHTING SYSTEM

UNSTABLE HANDLING

UNSTABLE HANDLING
Handlebar

●

Improperly installed or bent

Steering

●

Incorrect toe-in

●

Bent steering stem

●

Improperly installed steering stem 

●

Damaged bearing or bearing race

●

Bent tie-rods

●

Deformed steering knuckles

Tires

●

Uneven tire pressures on both sides

●

Incorrect tire pressure

●

Uneven tire wear

Wheels

●

Deformed wheel

●

Loose bearing 

●

Bent or loose wheel axle

●

Excessive wheel runout

Frame

●

Bent

●

Damaged frame

LIGHTING SYSTEM

HEADLIGHT DARK

●

Improper bulb

●

Too many electric accessories

●

Hard charging (broken charging coil and/or
faulty rectifier/regulator)

●

Incorrect connection

●

Improperly grounded

●

Poor contacts (main or light switch)

●

Bulb life expired

BULB BURNT OUT

●

Improper bulb

●

Faulty battery

●

Faulty rectifier/regulator

●

Improperly grounded

●

Faulty main and/or light switch

●

Bulb life expired

YAMAHA MOTOR CO., LTD.

2500 SHINGAI IWATA SHIZUOKA JAPAN

YFM45FAR/YFM450FAR WIRING DIAGRAM

W

/

B B B

/

R

B

/

R B W

/

B

C

D

O B

B O

L

B

B

L

Y Br

B

B

B

/

Y B

B

B

(GRAY)

(GRAY)

D

WIRE HARNESS

SUB-WIRE 

HARNESS 4

Br Sb L

/

B

R

/

B Br

/

B B

/

Y

L

/

B Sb Br

B

/

Y Br

/

B R

/

B

Br Y

L

L

/

B G

B

L

Y R

/

Y

B G L

/

B

W Sb G

/

L

L

/

W B

/

R W

/

L

G

/

L Sb W

W

/

L B

/

R L

/

W

W

/

R Sb

L

/

W G

/

W

Sb W

/

R

G

/

W L

/

W

W

/

B L

/

Y

Br W

/

R

L

/

Y W

/

B

W

/

R Br

W

/

G R

W

/

R W

/

G

R W

/

G

W

/

L W

/

R

R Br

R Br

/

L

Br R

Br

/

L R

L

/

G L

/

R

L

/

B Sb

L

/

R L

/

G

Sb L

/

B

R

L

/

W L

/

B

R

/

B L

/

W O B

B

/

Y R W

/

R W

/

G

W

Y

/

B

B

/

R

G

/

L

G

/

W W

/

B

Sb G

/

R

(BLACK)

(BLACK)

(BLACK)

C

WIRE HARNESS

SUB-WIRE 

HARNESS 3

B

WIRE HARNESS

SUB-WIRE 

HARNESS 2

A

WIRE HARNESS

SUB-WIRE 

HARNESS 1

(BLACK)

(BLACK)

(BLACK)

(GRAY)

(GRAY)

(GRAY)

(GRAY)

(BLACK)

(BLACK)

Gy G

/

R

Br B

G

/

R Gy

B Br

(GRAY)

(GRAY)

W

W W

W

W W

OFF

ON

OFF

2WD
4WD

LOCK

W

/

G

Br

/

L

R

/

G

L

/

B

G

/

W

G

/

W

L

/

W

Br

Br

W

/

R

W

/

G

R

W

/

G

W

/

R

L

/

W

L

/

Y

R

/

B

G

/

W

Y

/

B

G

/

R

Sb

G

/

L

W

/

B

B

/

R

B

/

Y

B

/

Y

L

/

Y

R

/

G

Br

/

R

B

/

R

W

/

B

G

/

L

G

/

R

W

/

L

W

/

L

R

Br

Sb

O

C

B

O

B

W

W

B

B

B

W

B

W
W
W

W
W
W

R

R

R

R

B

W

W

W

R

B

B

PUSH

_

R

R

B

B

B

B

B

B

R

R

R

D

W

/

R

W

/

R

D

L

/

W

B

/

R

B

/

R

L

/

W

D

A

Br

/

B

Br

/

B

Br

/

B

B

B

W

/

B

W

/

B

W

/

B

A

Sb

Sb

O

/

R

P

B

/

W

L

/

Y W

B

G

/

R

R

/

G

B

G

/

R R

/

G

B

Y

G

B

Y G

B

Y G

B

B

/

Y

Br

/

R

Br

/

R

L

/

R

B

(BLACK)

Br

/

B

Br

/

R

Br

/

R

L

/

G

B

(BLACK)

Br

/

R

L

/

R

B

/

Y

Br

/

R

B

Br

/

R

L

/

G

Br

/

B

B

B

B

B

B

Br

Sb

L

/

B

L

/

G

Br

B

/

Y

Sb

L

/

B

B

/

Y

L

/

R

Y

/

B

Br

/

R

L

/

R

Gy

Gy

G

/

R

Br

/

B W

/

B

B

B

/

Y

B

/

R

B

L

/

B

Sb

Br

B

B

B

B

A

Y

/

B Gy

Br

/

R L

/

R

Br

/

L

Br

/

R

Br

/

L

L

/

B

R

/

B

Br

/

L

R

/

W

R

/

W

Br

/

L

R

/

Y

Br

/

L

Br

R

/

B

R

/

B

R

/

Y

P

B

B

B

G

Y

G

Y

B

L

L

L

PUSH

_

Br

B

B

P

(BLACK)

(BLACK)

R

/

B

R

/

W

R

/

B R

/

W

B

G

Y

B

L

Y

Y

G

B

(DARK GRAY)

(BLACK) (BLACK)

L

R

/

B

Br

Y

Y Br

B

B

(BLACK) (BLACK)

Br

Y

Br

B

Br

B

1

2

3

4

5

6

7

8

9

0

A

B

C

D

E

F

G

H I J K L M

O

P

Q

R

S

T

U

V

W

Y

\

]

b

d

e

i

g

j

k

h

b

^

a

X

Z

[

c

f

N

1

A.C. magneto

2

Rectifier/regulator

3

Main switch

4

Backup fuse

5

Battery

6

Main fuse

7

Starter relay

8

Starter motor

9

Reverse switch

0

CDI unit

A

Rear brake switch

B

Ignition coil

C

Spark plug

D

Speed sensor

E

Thermo switch 1

F

Meter assembly

G

Multi-function meter

H

Differential gear lock indicator light

I

Coolant temperature warning light

J

Reverse indicator light

K

Neutral indicator light

L

Park indicator light

M

High-range indicator light

N

Low-range indicator light

O

Low-range switch

P

High-range switch

Q

Neutral switch

R

Four-wheel drive fuse

S

Four-wheel drive relay 1

T

Four-wheel drive relay 2

U

Four-wheel drive relay 3

V

On-command four-wheel drive switch and 
differential gear lock switch

W

Gear motor

X

Auxiliary DC jack fuse

Y

Auxiliary DC jack

Z

Ignition fuse

[

Headlight fuse

\

Handlebar switch (left)

]

Light switch

^

Engine stop switch

a

Start switch

b

Headlight

c

Circuit breaker (fan motor)

d

Thermo switch 2

e

Fan motor

f

Signaling system fuse

g

Front brake light switch 

h

Rear brake light switch

i

Tail/brake light

j

Horn switch

k

Horn

È

For Europe and Oceania

COLOR CODE

B ............Black
Br ...........Brown
G............Green
L.............Blue
O............Orange
P ............Pink
R ............Red
Sb ..........Sky blue
Gy ..........Gray

W ...........White
Y ............Yellow
B/R.........Black/Red
B/Y.........Black/Yellow
Br/B........Brown/Black
Br/L ........Brown/Blue
Br/R .......Brown/Red
G/L .........Green/Blue
G/R ........Green/Red

G/W........Green/White
G/Y.........Green/Yellow
L/B .........Blue/Black
L/G .........Blue/Green
L/R .........Blue/Red
L/W ........Blue/White
L/Y .........Blue/Yellow
R/B.........Red/Black
R/G ........Red/Green

R/W ....... Red/White
R/Y ........ Red/Yellow
W/B ....... White/Black
W/G....... White/Green
W/L ....... White/Blue
W/R ....... White/Red
Y/B ........ Yellow/Black