Yamaha XV19SW(C), XV19W(C), XV19MW(C), XV19CTSW(C), XV19CTW(C), XV19CTMW(C). Service Manual - part 16

CAMSHAFTS

5-32

Bolts “2”: l = 45 mm (1.77 in)
Bolts “3”: l = 70 mm (2.76 in)

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EAS24080

INSTALLING THE CYLINDER HEAD 
COVERS

1. Install:

• Rear cylinder head cover “1”
• Front cylinder head cover “2”

NOTE:

Due to the small clearance between the frame 
and the rear cylinder head cover, the three bolts 
“3” cannot be installed when the cover is in 
place. Set the bolts in the cylinder head cover, 
and then install the cover from the right side of 
the vehicle.

Bolts “4”: l = 40 mm (1.57 in)
Bolts “5”: l = 60 mm (2.36 in)

ET1D71032

INSTALLING THE SHIFT PEDAL ASSEMBLY

1. Install:

• Shift pedal assembly “1”

NOTE:

Align the mark “a” on the shift pedal shaft with 
the slot in the shift pedal.

T

 

R

.

 

Cylinder head cover bolt

10 Nm (1.0 m·kg, 7.2 ft·lb)

1

3

2

1

4

5

5

5

5

2

4

5

5

5

5

3

3

3

a

1

CYLINDER HEADS

5-33

EAS24110

CYLINDER HEADS

Removing the cylinder heads

Order

Job/Parts to remove

Q’ty

Remarks

Cylinder-#1 ignition coil bracket

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

Throttle bodies/Intake manifolds

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

Cylinder head covers/Rocker arms

Refer to “CAMSHAFTS” on page 5-14.

1

Engine bracket (right upper side)

1

2

Engine bracket (left upper side)

1

3

Engine temperature sensor

1

4

Oil pipe 1

1

5

Copper washer

4

6

Copper washer

2

7

Rear cylinder head

1

8

Front cylinder head

1

9

Cylinder head gasket

2

10

Dowel pin

4

11

Rear exhaust pipe joint cover

1

12

Rear exhaust pipe joint

1

4

13

3

8

9

10

1

11

5

2

12

7

9

5

6

10

 

R

18 Nm (1.8 m 

•

 

kg, 13 ft

 

•

 

Ib)

T

 

R

20 Nm (2.0 m 

•

 

kg, 14 ft

 

•

 

Ib)

T

 

R

59 Nm (5.9 m 

•

 

kg, 43 ft

 

•

 

Ib)

T

 

R

53 Nm (5.3 m 

•

 

kg, 38 ft

 

•

 

Ib)

T

 

R

66 Nm (6.6 m 

•

 

kg, 48 ft

 

•

 

Ib)

T

 

R

53 Nm (5.3 m 

•

 

kg, 38 ft

 

•

 

Ib)

 

R

20 Nm (2.0 m 

•

 

kg, 14 ft

 

•

 

Ib)

 

R

10 Nm (1.0 m 

•

 

kg, 7.2 ft

 

•

 

Ib)

 

R

60 Nm (6.0 m 

•

 

kg, 43 ft

 

•

 

Ib)

T

 

R

21 Nm (2.1 m 

•

 

kg, 15 ft

 

•

 

Ib)

New

LT

E

New

New

New

New

New

New

New

LT

(3)

CYLINDER HEADS

5-34

13

Rear exhaust pipe gasket

1

For installation, reverse the removal proce-
dure.

Removing the cylinder heads

Order

Job/Parts to remove

Q’ty

Remarks

4

13

3

8

9

10

1

11

5

2

12

7

9

5

6

10

 

R

18 Nm (1.8 m 

•

 

kg, 13 ft

 

•

 

Ib)

T

 

R

20 Nm (2.0 m 

•

 

kg, 14 ft

 

•

 

Ib)

T

 

R

59 Nm (5.9 m 

•

 

kg, 43 ft

 

•

 

Ib)

T

 

R

53 Nm (5.3 m 

•

 

kg, 38 ft

 

•

 

Ib)

T

 

R

66 Nm (6.6 m 

•

 

kg, 48 ft

 

•

 

Ib)

T

 

R

53 Nm (5.3 m 

•

 

kg, 38 ft

 

•

 

Ib)

 

R

20 Nm (2.0 m 

•

 

kg, 14 ft

 

•

 

Ib)

 

R

10 Nm (1.0 m 

•

 

kg, 7.2 ft

 

•

 

Ib)

 

R

60 Nm (6.0 m 

•

 

kg, 43 ft

 

•

 

Ib)

T

 

R

21 Nm (2.1 m 

•

 

kg, 15 ft

 

•

 

Ib)

New

LT

E

New

New

New

New

New

New

New

LT

(3)

CYLINDER HEADS

5-35

EAS24140

REMOVING THE CYLINDER HEADS

1. Remove:

• Cylinder head nuts

NOTE:

• Loosen the nuts in the proper sequence as 

shown.

• Loosen each nut 1/2 of a turn at a time. After all 

of the nuts are fully loosened, remove them.

EAS24170

CHECKING THE CYLINDER HEADS

The following procedure applies to all of the cyl-
inder heads.
1. Eliminate:

• Combustion chamber carbon deposits

(with a rounded scraper)

NOTE:

Do not use a sharp instrument to avoid damag-
ing or scratching:
• Spark plug bore threads
• Valve seats

2. Check:

• Cylinder head

Damage/scratches 

→

 Replace.

3. Measure:

• Cylinder head warpage

Out of specification 

→

 Resurface the cylinder 

head.

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a. Place a straightedge and a thickness gauge 

across the cylinder head.

b. Measure the warpage.
c. If the limit is exceeded, resurface the cylinder 

head as follows.

d. Place a 400–600 grit wet sandpaper on the 

surface plate and resurface the cylinder head 
using a figure-eight sanding pattern.

NOTE:

To ensure an even surface, rotate the cylinder 
head several times.

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EAS24220

CHECKING THE OIL PIPE

1. Check:

• Oil pipe 1

Damage 

→

 Replace.

Obstruction 

→

 Wash and blow out with com-

pressed air.

A. Front cylinder
B. Rear cylinder

2

4

3

1

A

2

4

3

1

B

 

Warpage limit

0.03 mm (0.0012 in)

CYLINDER HEADS

5-36

EAS24250

INSTALLING THE CYLINDER HEADS

1. Install:

• Cylinder head gasket “1” 
• Dowel pins “2”

NOTE:

The “1D7” mark on the cylinder head gasket 
must face up and towards the left side of the cyl-
inder.

2. Install:

• Cylinder heads
• Washers
• Cylinder head nuts

NOTE:

Lubricate the cylinder head nuts and washers 
with engine oil.

3. Tighten:

• Cylinder head nuts

NOTE:

Tighten the cylinder head nuts in the proper 
tightening sequence as shown and torque them 
in two stages.

4. Install:

• Copper washers 
• Oil pipe 1
• Oil pipe union bolt (M8)

• Oil pipe union bolts (M10)

NOTE:

Tighten the three union bolts evenly, and then 
torque them to specification.

5. Install:

• Engine bracket (right upper side)
• Engine bracket bolts (right upper side)
• Engine mounting bolts (right upper side)
• Engine bracket (left upper side)
• Engine bracket bolts (left upper side)
• Engine mounting bolts (left upper side)

NOTE:

• Apply locking agent (LOCTITE

®

) to the threads 

of the engine mounting bolts (left upper side).

• Do not fully tighten the bolts.

6. Tighten:

• Engine mounting bolts (right upper side)
• Engine mounting bolts (left upper side)
• Engine bracket bolts (right upper side)
• Engine bracket bolts (left upper side)

T

 

R

.

 

Cylinder head nut

60 Nm (6.0 m·kg, 43 ft·lb)

New

2

2

1

New

3

1

2

4

A

A. Front cylinder
B. Rear cylinder

T

 

R

.

 

Oil pipe union bolt (M8)

18 Nm (1.8 m·kg, 13ft·lb)

T

 

R

.

 

Oil pipe union bolt (M10)

21 Nm (2.1 m·kg, 15 ft·lb)

3

1

2

4

B

New

CYLINDER HEADS

5-37

T

 

R

.

 

Engine mounting bolt (right up-
per side)

59 Nm (5.9 m·kg, 43 ft·lb)

Engine mounting bolt (left upper 
side)

66 Nm (6.6 m·kg, 48 ft·lb)
LOCTITE

®

Engine bracket bolt (right upper 
side)

53 Nm (5.3 m·kg, 38 ft·lb)

Engine bracket bolt (left upper 
side)

53 Nm (5.3 m·kg, 38 ft·lb)

VALVES AND VALVE SPRINGS

5-38

EAS24270

VALVES AND VALVE SPRINGS

Removing the valves and valve springs

Order

Job/Parts to remove

Q’ty

Remarks

The following procedure applies to both cyl-
inders.

Cylinder heads

Refer to “CYLINDER HEADS” on page 5-33.

1

Valve cotter

8

2

Upper spring seat

4

3

Valve spring

4

4

Intake valve

2

5

Exhaust valve

2

6

Valve stem seal

4

7

Lower spring seat

4

8

Valve guide

4

For installation, reverse the removal proce-
dure.

1

M

E

M

E

New

New

New

New

M

M

7

3

6

2

1

7

3

6

2

1

8

8

8

7

3

6

2

7

3

6

2

1

8

4 5

VALVES AND VALVE SPRINGS

5-39

EAS24280

REMOVING THE VALVES

The following procedure applies to all of the 
valves and related components.

NOTE:

Before removing the internal parts of the cylinder 
head (e.g., valves, valve springs, valve seats), 
make sure the valves properly seal.

1. Check:

• Valve sealing

Leakage at the valve seat 

→

 Check the valve 

face, valve seat, and valve seat width.
Refer to “CHECKING THE VALVE SEATS” 
on page 5-41.

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a. Pour a clean solvent “a” into the intake and 

exhaust ports.

b. Check that the valves properly seal.

NOTE:

There should be no leakage at the valve seat “1”.

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2. Remove:

• Valve cotters

NOTE:

Remove the valve cotters by compressing the 
valve springs with the valve spring compressor 
set “1”.

3. Remove:

• Upper spring seat “1”
• Valve spring “2”
• Valve “3”
• Valve stem seal “4”
• Lower spring seat “5”

NOTE:

Identify the position of each part very carefully so 
that it can be reinstalled in its original place.

EAS24290

CHECKING THE VALVES AND VALVE 
GUIDES

The following procedure applies to all of the 
valves and valve guides.
1. Measure:

• Valve-stem-to-valve-guide clearance

Out of specification 

→

 Replace the valve 

guide.

 

Valve spring compressor

90890-04019
YM-04019

• Valve-stem-to-valve-guide clearance =

Valve guide inside diameter “a” -
Valve stem diameter “b”

VALVES AND VALVE SPRINGS

5-40

2. Replace:

• Valve guide

NOTE:

To ease valve guide removal and installation, 
and to maintain the correct fit, heat the cylinder 
head to 100 °C (212 °F) in an oven.

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a. Remove the valve guide with the valve guide 

remover “1”.

b. Install the new valve guide with the valve 

guide installer “2” and valve guide remover 
“1”.

c. After installing the valve guide, bore the valve 

guide with the valve guide reamer “3” to ob-
tain the proper valve-stem-to-valve-guide 
clearance.

NOTE:

After replacing the valve guide, reface the valve 
seat.

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3. Eliminate:

• Carbon deposits

(from the valve face and valve seat)

4. Check:

• Valve face

Pitting/wear 

→

 Grind the valve face.

 

Valve-stem-to-valve-guide clear-
ance (intake)

0.010–0.037 mm (0.0004–0.0015 
in)

Limit

0.080 mm (0.0032 in)

Valve-stem-to-valve-guide clear-
ance (exhaust)

0.025–0.052 mm (0.0010–0.0020 
in)

Limit

0.100 mm (0.0039 in)

 

Valve guide remover (ø6)

90890-04064

Valve guide remover (6.0 mm)

YM-04064-A

Valve guide installer (ø6)

90890-04065

Valve guide installer (6.0 mm)

YM-04065-A

Valve guide reamer (ø6)

90890-04066

Valve guide reamer (6.0 mm)

YM-04066

VALVES AND VALVE SPRINGS

5-41

• Valve stem end

Mushroom shape or diameter larger than the 
body of the valve stem 

→

 Replace the valve.

5. Measure:

• Valve margin thickness D “a”

Out of specification 

→

 Replace the valve.

6. Measure:

• Valve stem runout

Out of specification 

→

 Replace the valve.

NOTE:

• When installing a new valve, always replace 

the valve guide.

• If the valve is removed or replaced, always re-

place the valve stem seal.

EAS24300

CHECKING THE VALVE SEATS

The following procedure applies to all of the 
valves and valve seats.

1. Eliminate:

• Carbon deposits

(from the valve face and valve seat)

2. Check:

• Valve seat

Pitting/wear 

→

 Replace the cylinder head.

3. Measure:

• Valve seat width C “a”

Out of specification 

→

 Replace the cylinder 

head.

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a. Apply Mechanic’s blueing dye (Dykem) “b” 

onto the valve face.

b. Install the valve into the cylinder head.
c. Press the valve through the valve guide and 

onto the valve seat to make a clear impres-
sion.

d. Measure the valve seat width.

NOTE:

Where the valve seat and valve face contacted 
one another, the blueing will have been re-
moved.

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Valve margin thickness D (intake)

1.15–1.45 mm (0.0453–0.0571 in)

Limit

0.4 mm (0.02 in)

Valve margin thickness D (ex-
haust)

1.15–1.45 mm (0.0453–0.0571 in)

Limit

0.4 mm (0.02 in)

 

Valve stem runout

0.010 mm (0.0004 in)

 

Valve seat width C (intake)

1.10–1.30 mm (0.0433–0.0512 in)

Limit

2.0 mm (0.08 in)

Valve seat width C (exhaust)

1.10–1.30 mm (0.0433–0.0512 in)

Limit

2.0 mm (0.08 in)

VALVES AND VALVE SPRINGS

5-42

4. Lap:

• Valve face
• Valve seat

NOTE:

After replacing the cylinder head or replacing the 
valve and valve guide, the valve seat and valve 
face should be lapped.

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a. Apply a coarse lapping compound “a” to the 

valve face.

CAUTION:

ECA13790

Do not let the lapping compound enter the 
gap between the valve stem and the valve 
guide.

b. Apply molybdenum disulfide oil onto the 

valve stem.

c. Install the valve into the cylinder head.
d. Turn the valve until the valve face and valve 

seat are evenly polished, then clean off all of 
the lapping compound.

NOTE:

For the best lapping results, lightly tap the valve 
seat while rotating the valve back and forth be-
tween your hands.

e. Apply a fine lapping compound to the valve 

face and repeat the above steps.

f. After every lapping procedure, be sure to 

clean off all of the lapping compound from the 
valve face and valve seat.

g. Apply Mechanic’s blueing dye (Dykem) “b” 

onto the valve face.

h. Install the valve into the cylinder head.
i. Press the valve through the valve guide and 

onto the valve seat to make a clear impres-
sion.

j. Measure the valve seat width “c” again. If the 

valve seat width is out of specification, reface 
and lap the valve seat.

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EAS24310

CHECKING THE VALVE SPRINGS

The following procedure applies to all of the 
valve springs.
1. Measure:

• Valve spring free length “a”

Out of specification 

→

 Replace the valve 

spring.

VALVES AND VALVE SPRINGS

5-43

2. Measure:

• Compressed valve spring force “a”

Out of specification 

→

 Replace the valve 

spring.

3. Measure:

• Valve spring tilt “a”

Out of specification 

→

 Replace the valve 

spring.

EAS24340

INSTALLING THE VALVES

The following procedure applies to all of the 
valves and related components.
1. Deburr:

• Valve stem end

(with an oil stone)

2. Lubricate:

• Valve stem “1”
• Valve stem seal “2”

(with the recommended lubricant)

3. Install:

• Valve guide “1”

 

Free length (intake)

46.71 mm (1.84 in)

Limit

44.71 mm (1.76 in)

Free length (exhaust)

46.71 mm (1.84 in)

Limit

44.71 mm (1.76 in)

 

Installed compression spring 
force (intake)

217.00–249.00 N (48.78–55.98 lb) 
(22.13–25.39 kgf)

Installed compression spring 
force (exhaust)

217.00–249.00 N (48.78–55.98 lb) 
(22.13–25.39 kgf)

Installed length (intake)

32.66 mm (1.29 in)

Installed length (exhaust)

32.66 mm (1.29 in)

b. Installed length

 

Spring tilt (intake)

2.5 °/2.0 mm

Spring tilt (exhaust)

2.5 °/2.0 mm

 

Recommended lubricant

Molybdenum disulfide oil

VALVES AND VALVE SPRINGS

5-44

• Lower spring seat “2”
• Valve stem seal “3”
• Valve “4”
• Valve spring “5”
• Upper spring seat “6”

(into the cylinder head)

NOTE:

• Make sure each valve is installed in its original 

place.

• Install the valve springs with the larger pitch “a” 

facing up.

4. Install:

• Valve cotters

NOTE:

Install the valve cotters by compressing the 
valve springs with the valve spring compressor 
set “1”.

5. To secure the valve cotters onto the valve 

stem, lightly tap the valve tip with a soft-face 
hammer.

CAUTION:

ECA13800

Hitting the valve tip with excessive force 
could damage the valve.

b. Smaller pitch

 

Valve spring compressor

90890-04019
YM-04019

CYLINDERS AND PISTONS

5-45

EAS24360

CYLINDERS AND PISTONS

Removing the cylinders and pistons

Order

Job/Parts to remove

Q’ty

Remarks

Cylinder heads

Refer to “CYLINDER HEADS” on page 5-33.

1

Front cylinder

1

2

Rear cylinder

1

3

Cylinder gasket

2

4

Dowel pin

4

5

Circlip

4

6

Piston pin

2

7

Piston

2

8

Top ring

2

9

2nd  ring

2

10

Oil ring

2

For installation, reverse the removal proce-
dure.

8

9

2

10

3

5

4

3

7

6

5

4

5

8

9

10

7

6

5

1

New

E

New

E

E

New

New

New

New

CYLINDERS AND PISTONS

5-46

EAS24380

REMOVING THE PISTON

1. Remove:

• Piston pin clips “1”
• Piston pin “2”
• Piston “3”

CAUTION:

ECA13810

Do not use a hammer to drive the piston pin 
out.

NOTE:

• Before removing the piston pin clip, cover the 

crankcase opening with a clean rag to prevent 
the piston pin clip from falling into the crank-
case.

• For reference during installation, put an identi-

fication mark on each piston crown.

• Before removing the piston pin, deburr the pis-

ton pin clip’s groove and the piston’s pin bore 
area. If both areas are deburred and the piston 
pin is still difficult to remove, remove it with the 
piston pin puller set “4”.

2. Remove:

• Top ring
• 2nd ring
• Oil ring

NOTE:

When removing a piston ring, open the end gap 
with your fingers and lift the other side of the ring 
over the piston crown.

EAS24410

CHECKING THE CYLINDERS AND PISTONS

The following procedure applies to all of the cyl-
inders and pistons.
1. Check:

• Piston wall
• Cylinder wall

Vertical scratches 

→

 Rebore or replace the 

cylinder, and replace the piston and piston 
rings as a set.

2. Measure:

• Piston-to-cylinder clearance

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a. Measure cylinder bore “C” with the cylinder 

bore gauge.

NOTE:

Measure cylinder bore “C” by taking side-to-side 
and front-to-back measurements of the cylinder. 
Then, find the average of the measurements.

 

Piston pin puller set

90890-01304

Piston pin puller

YU-01304

3

2

1

 

Bore

100.000–100.010 mm (3.9370–
3.9374 in)

Taper limit

0.050 mm (0.0020 in)

Out of round limit

0.050 mm (0.0020 in)

“C” = maximum of D

1

–D

6

“T” = maximum of D

1

 or D

2

 - maximum of D

5

 

or D

6

“R” = maximum of D

1

, D

3

 or D

5

 - minimum of 

D

2

, D

4

 or D

6

CYLINDERS AND PISTONS

5-47

b. If out of specification, rebore or replace the 

cylinder, and replace the piston and piston 
rings as a set.

c. Measure piston skirt diameter D “a” with the 

micrometer.

d. If out of specification, replace the piston and 

piston rings as a set.

e. Calculate the piston-to-cylinder clearance 

with the following formula.

f. If out of specification, rebore or replace the 

cylinder, and replace the piston and piston 
rings as a set.

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EAS24430

CHECKING THE PISTON RINGS

1. Measure:

• Piston ring side clearance

Out of specification 

→

 Replace the piston 

and piston rings as a set.

NOTE:

Before measuring the piston ring side clearance, 
eliminate any carbon deposits from the piston 
ring grooves and piston rings.

2. Install:

• Piston ring

(into the cylinder)

NOTE:

Level the piston ring into the cylinder with the 
piston crown.

 

Piston

Diameter D

99.960–99.975 mm (3.9354–
3.9360 in)

b. 10 mm (0.39 in) from the bottom edge of the 

piston

• Piston-to-cylinder clearance =

Cylinder bore “C” -
Piston skirt diameter “D”

 

Piston-to-cylinder clearance

0.025–0.050 mm (0.0010–0.0020 
in)

Limit

0.15 mm (0.0059 in)

 

Piston ring

Top ring

Ring side clearance

0.030–0.080 mm (0.0012–
0.0032 in)

Limit

0.120 mm (0.0047 in)

2nd ring

Ring side clearance

0.030–0.070 mm (0.0012–
0.0028 in)

Limit

0.120 mm (0.0047 in)

a. 10 mm (0.39 in)