Yamaha XV19SW(C), XV19W(C), XV19MW(C), XV19CTSW(C), XV19CTW(C), XV19CTMW(C). Service Manual - part 21

TRANSMISSION

5-112

3. Check:

• Transmission gears

Blue discoloration/pitting/wear 

→

 Replace 

the defective gear(s).

• Transmission gear dogs

Cracks/damage/rounded edges 

→

 Replace 

the defective gear(s).

4. Check:

• Transmission gear engagement

(each pinion gear to its respective wheel 
gear)
Incorrect 

→

 Reassemble the transmission 

axle assemblies.

5. Check:

• Transmission gear movement

Rough movement 

→

 Replace the defective 

part(s).

6. Check:

• Circlips

Bends/damage/looseness 

→

 Replace.

ET1D71006

ASSEMBLING THE MAIN AXLE AND DRIVE 
AXLE

1. Install:

• Toothed washer “1”

• Circlip “2” 

NOTE:

• Be sure the circlip sharp-edged corner “a” is 

positioned opposite side to the toothed washer 
and gear. (For main axle)

• Install the circlip so that both ends “b” rest on 

the sides of a spline “c” with both axles aligned.

2. Install:

• Toothed lock washer retainer “1”
• Toothed lock washer “2”

NOTE:

• With the toothed lock washer retainer “1” in the 

groove “a” in the axle, align the projection “c” 
on the retainer with an axle spline “b”, and then 
install the toothed lock washer “2”.

• Be sure to align the projection on the toothed 

lock washer that is between the alignment 
marks “e” with the alignment mark “d” on the 
retainer.

EAS26320

INSTALLING THE SHIFT FORKS AND SHIFT 
DRUM ASSEMBLY

1. Install:

• Shift forks 1 “1”
• Shift fork 2 “2”
• Shift drum assembly “3”

New

1

2

2

New

a

b

c

2

e

e

d

b

c

1

c

b

a

2

1

TRANSMISSION

5-113

• Shift fork guide bars “4”

NOTE:

The embossed marks “1D7” on the shift forks 
should face towards the left side of the engine.

2. Check:

• Transmission

Rough movement 

→

 Repair.

NOTE:

• Apply engine oil to each gear and bearing thor-

oughly.

• Before assembling the crankcase, make sure 

that the transmission is in neutral and that the 
gears turn freely.

3

4

4

2

1

6

FUEL SYSTEM

FUEL TANK

.................................................................................................... 6-1

REMOVING THE FUEL TANK.................................................................. 6-3
REMOVING THE FUEL PUMP ................................................................. 6-3
CHECKING THE FUEL PUMP BODY ...................................................... 6-4
CHECKING THE FUEL PUMP OPERATION ........................................... 6-4
INSTALLING THE FUEL PUMP................................................................ 6-4
INSTALLING THE FUEL TANK ................................................................ 6-4

THROTTLE BODIES

....................................................................................... 6-6

REMOVING THE FUEL HOSE ............................................................... 6-11
CHECKING THE INJECTORS................................................................ 6-11
CHECKING THE THROTTLE BODIES................................................... 6-11
CHECKING THE ROLLOVER VALVES.................................................. 6-11
CHECKING THE PRESSURE REGULATOR ......................................... 6-11
CHECKING THE PRESSURE REGULATOR OPERATION................... 6-11
ADJUSTING THE THROTTLE POSITION SENSOR ............................. 6-12
INSTALLING THE FUEL PIPE................................................................ 6-12
INSTALLING THE FUEL HOSE.............................................................. 6-13

ISC (IDLE SPEED CONTROL) UNIT

............................................................ 6-14

CHECKING THE ISC (IDLE SPEED CONTROL) SYSTEM ................... 6-15

FUEL TANK

6-1

EAS26620

FUEL TANK

Removing the fuel tank

Order

Job/Parts to remove

Q’ty

Remarks

Rider seat/Rider seat bracket

Refer to “GENERAL CHASSIS” on page 
4-1.

1

Meter assembly coupler

3

Disconnect.

2

Meter cover

1

3

Fuel sender coupler

1

Disconnect.

4

Fuel tank breather hose

1

Disconnect.

5

Air vent hose (fuel pump to fuel hose joint)

1

Disconnect.

6

Fuel tank

1

7

Fuel tank bracket (rear side)

1

8

Fuel tank bracket (front side)

1

9

Fuel sender

1

For installation, reverse the removal proce-
dure.

2

6

1

8

3

5

9

7

 

R

4 Nm (0.4 m

 

•

 kg, 2.9 ft 

•

 Ib)

T

 

R

16 Nm (1.6 m 

•

 

kg, 11 ft

 

•

 

Ib)

 

R

7 Nm (0.7 m

 

•

 kg, 5.1 ft 

•

 Ib)

 

R

10 Nm (1.0 m 

•

 

kg, 7.2 ft

 

•

 

Ib)

T

 

R

7 Nm (0.7 m

 

•

 kg, 5.1 ft 

•

 Ib)

4

(4)

FUEL TANK

6-2

Removing the fuel pump and sub-fuel tank

Order

Job/Parts to remove

Q’ty

Remarks

Rider seat/Rider seat bracket

Refer to “GENERAL CHASSIS” on page 
4-1.

Fuel tank

Refer to “FUEL TANK” on page 6-1.

1

Fuel pump coupler

1

Disconnect.

2

Fuel hose connector cover

1

3

Fuel outlet hose

1

Disconnect.

4

Air vent hose (fuel pump to fuel hose joint)

1

5

Fuel return hose (fuel return pipe to sub-fuel 
tank)

1

Disconnect.

6

Fuel pump bracket

1

7

Fuel pump gasket

1

8

Fuel pump

1

9

Sub-fuel tank

1

For installation, reverse the removal proce-
dure.

8

9

1

3

4

5

6

7

T

 

R

5 Nm (0.5 m

 

•

 kg, 3.6 ft 

•

 Ib)

 

R

10 Nm (1.0 m

 

•

 kg, 7.2 ft 

•

 Ib)

(3)

New

New

(6)

(3)

(3)

2

FUEL TANK

6-3

EAS26630

REMOVING THE FUEL TANK

1. Extract the fuel in the fuel tank through the 

fuel tank cap with a pump.

2. Remove:

• Fuel tank

CAUTION:

EC1D71021

Although the fuel has been removed from 
the fuel tank, be careful when removing the 
fuel hoses, since there may be fuel remain-
ing in them.

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▼

▼ ▼▼▼

▼

▼ ▼▼▼

▼

▼ ▼▼▼

▼

▼ ▼▼▼

▼

▼▼▼

a. Remove the fuel hose joint caps “1”.

NOTE:

After removing the fuel hose joint caps, clean the 
projection on each cap so that no foreign mate-
rial will enter the fuel lines.

b. Lubricate the O-ring “1” with the recommend-

ed silicone lubricant “2”.

NOTE:

Spray the silicone lubricant in the areas shown in 
the illustration.

c. Turn the screws “1” clockwise.

NOTE:

Turn the screws until they stop.

d. Disconnect the fuel hose (fuel hose joint to 

fuel pump) “1” and air vent hose (fuel pump to 
fuel hose joint) “2”.

NOTE:

Before removing the hoses, place a few rags in 
the area under where they will be removed.

e. Install the fuel hose joint cap “1” and rubber 

plug “2”.

NOTE:

Insert the projection on the fuel hose joint cap 
completely into the pipe of the fuel hose joint and 
insert the rubber plug into the end of the fuel 
hose (fuel hose joint to fuel pump).

f. Remove the fuel tank.

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▲

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▲

▲ ▲▲▲

▲

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▲

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EAS26640

REMOVING THE FUEL PUMP

1. Remove:

• Fuel hose connector cover

2. Disconnect:

• Fuel outlet hose

 

Recommended lubricant

Silicone protectant and lubri-
cant
ACC-SLCNS-PR-AY

1

2

1

1

1

2

1

1

2

FUEL TANK

6-4

CAUTION:

EC1D71022

• Be sure to disconnect the fuel outlet hose 

by hand. Do not forcefully disconnect the 
hose with tools.

• Although the fuel has been removed from 

the fuel tank be careful when removing the 
fuel hoses, since there may be fuel remain-
ing in them.

NOTE:

• Remove the fuel hose manually without using 

any tools.

• Before removing the hoses, place a few rags in 

the area under where they will be removed.

3. Remove:

• Fuel pump

CAUTION:

ECA14720

• Do not drop the fuel pump or give it a 

strong shock.

• Do not touch the base section of the fuel 

sender.

EAS26670

CHECKING THE FUEL PUMP BODY

1. Check:

• Fuel pump body

Obstruction 

→

 Clean.

Cracks/damage 

→

 Replace fuel pump as-

sembly.

2. Check:

• Diaphragms and gaskets

Tears/fatigue/cracks 

→

 Replace fuel pump 

assembly.

EAS26690

CHECKING THE FUEL PUMP OPERATION

1. Check:

• Fuel pump operation

Refer to “CHECKING THE FUEL PUMP” on 
page 7-89.

EAS26710

INSTALLING THE FUEL PUMP

1. Install:

• Fuel pump

NOTE:

• Do not damage the installation surfaces of the 

sub-fuel tank when installing the fuel pump.

• Always use a new fuel pump gasket.

• Install the fuel pump as shown in the illustra-

tion.

• Align the projection “a” on the fuel pump with 

the slot in the fuel pump bracket.

• Tighten the fuel pump bolts in the proper tight-

ening sequence as shown.

2. Connect:

• Fuel outlet hose

3. Install:

• Fuel hose connector cover “1”

CAUTION:

EC1D71023

When installing the fuel outlet hose, make 
sure that it is securely connected, and that 
the fuel hose connector cover is installed 
correctly, otherwise the fuel outlet hose will 
not be properly installed.

NOTE:

• Install the fuel outlet hose connector securely 

onto the sub fuel tank until a distinct “click” is 
heard, and then make sure that it does not 
come loose.

• Install the holder “a” of the fuel hose connector 

cover, and then install the holder “b”. After in-
stalling the fuel hose connector cover, make 
sure that it is installed securely.

ET1D71025

INSTALLING THE FUEL TANK

1. Install:

• Fuel tank

T

 

R

.

 

Fuel pump bolt

5 Nm (0.5 m·kg, 3.6 ft·lb)

a

1

b

FUEL TANK

6-5

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▼

▼ ▼▼▼

▼

▼ ▼▼▼

▼

▼ ▼▼▼

▼

▼ ▼▼▼

▼

▼ ▼▼▼

▼

▼▼▼

a. Install the fuel tank.
b. Remove the fuel hose joint caps.
c. Connect the fuel hose (fuel hose joint to fuel 

pump) and air vent hose (fuel pump to fuel 
hose joint).

d. Turn the screws “1” counterclockwise.

NOTE:

Turn the screws until they contact the clips “a”.

e. Install the fuel hose joint caps.

NOTE:

Install the fuel hose joint caps completely onto 
the fuel hose joints.

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▲

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▲

▲ ▲▲▲

▲

▲ ▲▲▲

▲

▲ ▲▲▲

▲

▲ ▲▲▲

▲

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2. Install:

• Meter assembly couplers
• Fuel sender coupler

NOTE:

Make sure that the couplers are positioned as 
shown in the illustration in the following order 
from left to right: fuel sender coupler “1”, 6-pin 
black meter assembly coupler “2”, 6-pin white 
meter assembly coupler “3”, and 3-pin black 
meter assembly coupler “4”.

a

a

1

1

1

2

3

4

THROTTLE BODIES

6-6

EAS26970

THROTTLE BODIES

Removing the rollover valves

Order

Job/Parts to remove

Q’ty

Remarks

1

Horn 1 connector

2

For California only
Disconnect.

2

Horn 1

1

For California only

3

Fuel tank breather hose

1

4

Canister purge hose

1

For California only

5

Rollover valve 1

1

6

Rollover valve 2

1

7

Rollover valve hose

4

8

Fuel tank breather/overflow hose

1

9

Canister

1

For California only

10

Canister breather hose

1

For California only

For installation, reverse the removal proce-
dure.

3

7

2

1

4

6

7

7

9

8

5

7

T

 

R

10 Nm (1.0 m 

•

 

kg, 7.2 ft

 

•

 

Ib)

 

7 Nm (0.7 m

 

•

 kg, 5.1 ft 

•

 Ib)

10

THROTTLE BODIES

6-7

Removing the pressure regulator

Order

Job/Parts to remove

Q’ty

Remarks

1

Pressure regulator cover

1

2

Fuel hose (intake manifold assembly to pres-
sure regulator)

1

3

Air filter case breather hose 1

1

4

Air filter case breather hose 2

1

5

Hose clamp

1

6

Pressure regulator

1

7

Fuel return hose

1

8

Fuel return pipe

1

9

Pressure regulator bracket

1

For installation, reverse the removal proce-
dure.

T

 

R

7 Nm (0.7 m

 

•

 

kg, 5.1 ft

 

•

 

Ib)

 

R

7 Nm (0.7 m

 

•

 

kg, 5.1 ft

 

•

 

Ib)

 

R

13 Nm (1.3 m 

•

 

kg, 9.4 ft

 

•

 

Ib)

8

7

5

4

3

6

1

9

2

THROTTLE BODIES

6-8

Removing the throttle bodies

Order

Job/Parts to remove

Q’ty

Remarks

Rider seat/Rider seat bracket

Refer to “GENERAL CHASSIS” on page 
4-1.

Fuel tank

Refer to “FUEL TANK” on page 6-1.

Air filter case

Refer to “GENERAL CHASSIS” on page 
4-1.

Cylinder-#1 ignition coil cover

Refer to “ENGINE REMOVAL” on page 5-1.

1

Throttle position sensor coupler

1

Disconnect.

2

Cylinder-#1 intake air pressure sensor hose

1

3

Cylinder-#2 intake air pressure sensor hose

1

4

Canister purge hose

1

For California only

5

Throttle cable

2

Disconnect.

6

Throttle body joint clamp screw

2

Loosen.

7

Throttle body

1

CAUTION:

EC1D71013

The throttle bodies should not be disas-
sembled.

8

Throttle position sensor

1

For installation, reverse the removal proce-
dure.

5

7

6

8

2

1

4

6

3

T

 

R

3 Nm (0.3 m

 

•

 

kg, 2.2 ft

 

•

 

Ib)

T

 

R

3 Nm (0.3 m

 

•

 

kg, 2.2 ft

 

•

 

Ib)

THROTTLE BODIES

6-9

Removing the intake manifolds

Order

Job/Parts to remove

Q’ty

Remarks

1

Engine temperature sensor coupler

1

Disconnect.

2

Sub-wire harness 2 coupler

2

Disconnect.

3

Fuel outlet hose

1

Disconnect.

4

Fuel hose (intake manifold assembly to pres-
sure regulator)

1

5

Cylinder-#2 ISC (idle speed control) unit outlet 
hose

1

Disconnect.

6

Cylinder-#1 ISC (idle speed control) unit outlet 
hose

1

Disconnect.

7

Intake manifold assembly

1

8

Gasket

2

For installation, reverse the removal proce-
dure.

(2)

(2)

2

1

8

4

7

8

5

3

6

New

New

T

 

R

10 Nm (1.0 m 

•

 

kg, 7.2 ft

 

•

 

Ib)

T

 

R

10 Nm (1.0 m 

•

 

kg, 7.2 ft

 

•

 

Ib)

THROTTLE BODIES

6-10

Disassembling the intake manifolds

Order

Job/Parts to remove

Q’ty

Remarks

1

Cylinder-#1 injector coupler

1

Disconnect.

2

Cylinder-#2 injector coupler

1

Disconnect.

3

Sub-wire harness 2

1

4

Fuel pipe

1

5

Injector joint 1

1

6

Injector joint 2

1

7

Injector

2

For assembly, reverse the disassembly pro-
cedure.

5

7

3

1

6

7

4

R

30 Nm (3.0 m 

•

 

kg, 22 ft

 

•

 

Ib)

New

New

New

New

New

New

New

New

2

T

 

R

5 Nm (0.5 m

 

•

 kg, 3.6 ft 

•

 Ib)

T

 

R

5 Nm (0.5 m

 

•

 kg, 3.6 ft 

•

 Ib)

THROTTLE BODIES

6-11

ET1D71026

REMOVING THE FUEL HOSE

1. Disconnect:

• Fuel hose (intake manifold assembly to pres-

sure regulator)

CAUTION:

EC1D71014

Although the fuel has been removed from 
the fuel tank be careful when removing the 
fuel hose, since there may be fuel remaining 
in it.

NOTE:

• To remove the fuel hose from the fuel pipe or 

pressure regulator, slide the fuel hose connec-
tor cover “1” on the end of the hose in the direc-
tion of the arrow shown, press the two buttons 
“2” on the sides of the connector, and then re-
move the hose.

• Remove the fuel hose manually without using 

any tools.

• Before removing the hoses, place a few rags in 

the area under where they will be removed.

EAS26980

CHECKING THE INJECTORS

1. Check:

• Injectors

Damage 

→

 Replace.

EAS26990

CHECKING THE THROTTLE BODIES

1. Check:

• Throttle bodies

Cracks/damage 

→

 Replace the throttle bod-

ies as a set.

2. Check:

• Fuel passages

Obstructions 

→

 Clean.

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▼

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▼

▼ ▼▼▼

▼

▼ ▼▼▼

▼

▼▼▼

a. Wash the throttle bodies in a petroleum- 

based solvent.
Do not use any caustic carburetor cleaning 
solution.

b. Blow out all of the passages with compressed 

air.

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▲

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ET1D71007

CHECKING THE ROLLOVER VALVES

1. Check:

• Rollover valve 1 “1”
• Rollover valve 2 “2”

Damage/faulty 

→

 Replace.

NOTE:

• Check that air flows smoothly only in the direc-

tion of the arrow shown in the illustration.

• The rollover valves must be in an upright posi-

tion when checking the airflow.

EAS27000

CHECKING THE PRESSURE REGULATOR

1. Check:

• Pressure regulator

Damage 

→

 Replace.

EAS27010

CHECKING THE PRESSURE REGULATOR 
OPERATION

1. Check:

• Pressure regulator operation

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▼

▼ ▼▼▼

▼

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a. Remove the pressure regulator cover.

Refer to “THROTTLE BODIES” on page 6-6.

b. Disconnect the fuel hose “1” from the pres-

sure regulator “2”.

c. Connect the fuel pressure adapter “3” be-

tween the fuel hose “1” and pressure regula-
tor “2”.

d. Connect the pressure gauge “4” to the fuel 

pressure adapter “3”.

e. Connect the vacuum/pressure pump gauge 

set “5” to the pressure regulator.

1

2

1

2

THROTTLE BODIES

6-12

f. Start the engine.
g. Measure the fuel pressure.

h. Use the vacuum/pressure pump gauge set to 

adjust the fuel pressure in relation to the vac-
uum pressure as described below.

NOTE:

The vacuum pressure should not exceed 100 
kPa (760 mmHg).

Faulty 

→

 Replace the pressure regulator.

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▲

▲ ▲▲▲

▲

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EAS27030

ADJUSTING THE THROTTLE POSITION 
SENSOR

1. Check:

• Throttle position sensor

Refer to “CHECKING THE THROTTLE PO-
SITION SENSOR” on page 7-89.

2. Adjust:

• Throttle position sensor angle

▼▼▼

▼

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▼

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▼

▼ ▼▼▼

▼

▼ ▼▼▼

▼

▼ ▼▼▼

▼

▼▼▼

a. Connect the throttle position sensor coupler 

to the throttle position sensor.

b. Connect the digital circuit tester to the throttle 

position sensor.

c. Measure the throttle position sensor voltage.
d. Adjust the throttle position sensor angle so 

that the voltage is within the specified range.

e. After adjusting the throttle position sensor an-

gle, tighten the throttle position sensor 
screws “3”.

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ET1D71008

INSTALLING THE FUEL PIPE

1. Install:

• Fuel pipe “1”

 

Vacuum/pressure pump gauge 
set

90890-06756

Pressure gauge

90890-03153

Fuel pressure adapter

90890-03176
YM-03176

 

Fuel pressure

392 kPa (3.92 kg/cm², 55.7 psi)

• Increase the vacuum pressure 

→

Fuel pressure is decreased

• Decrease the vacuum pressure 

→

Fuel pressure is increased

1

2

4

2

5

3

1

• Positive tester probe

yellow terminal “1”

• Negative tester probe

black terminal “2”

 

Digital circuit tester

90890-03174

Model 88 Multimeter with ta-
chometer

YU-A1927

 

Output voltage (at idle)

0.63–0.73 V

T

 

R

.

 

Fuel pipe bolt

30 Nm (3.0 m·kg, 22 ft·lb)

3

3

1

2

THROTTLE BODIES

6-13

NOTE:

Install the fuel pipe “1” so that it contacts the pro-
jections “a” on the injector joints.

ET1D71027

INSTALLING THE FUEL HOSE

1. Connect:

• Fuel hose (intake manifold assembly to pres-

sure regulator)

CAUTION:

EC1D71015

When installing the fuel hose, make sure that 
it is securely connected, and that the fuel 
hose connector cover on the fuel hose is in 
the correct position, otherwise the fuel hose 
will not be properly installed.

NOTE:

• Install the fuel hose securely onto the fuel pipe 

or pressure regulator until a distinct “click” is 
heard.

• To install the fuel hose onto the fuel pipe or 

pressure regulator, slide the fuel hose connec-
tor cover “1” on the end of the hose in the direc-
tion of the arrow shown.

1

1

a

a

1