Yamaha Mt 01 T 2005 Manual

							CYLINDER HEADS
5-32
EAS24140REMOVING 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.
EAS24170CHECKING 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 seats2. Check:
Cylinder head
Damage/scratches → Replace.
3. Measure:
Cylinder head warpage
Out of specification → Resurface the cylinder 
head.



 





 
 



 
 



 
 



 
 



 



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.
          
EAS24220
CHECKING THE OIL PIPE
1. Check:
Oil pipe
Damage → Replace.
Obstruction → Wash and blow out with com-
pressed air.
A. Front cylinder
B. Rear cylinder
1
3
5 64
2
B 
Warpage limit
0.03 mm (0.0012 in) 
						

							CYLINDER HEADS
5-33
EAS24250INSTALLING THE CYLINDER HEADS
1. Tighten:
Cylinder head nuts (M12) “1”–“4”
Cylinder head nuts (M10) “5”, “6”
NOTE:
Lubricate the cylinder head nuts with engine 
oil.
Tighten the cylinder head nuts in the proper 
tightening sequence as shown and torque 
them in two stages.
T R.. 
Cylinder head nut (M12)
45 Nm (4.5 m·kg, 32 ft·lb)
T R.. 
Cylinder head nut (M10)
39 Nm (3.9 m·kg, 28 ft·lb)
A. Front cylinder
B. Rear cylinder
6
4
2 13
5
B 
						

							VALVES AND VALVE SPRINGS
5-34
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 
cylinders.
Cylinder heads Refer to “CYLINDER HEADS” on page 5-31.
1 Valve cotter 8
2 Upper spring seat 4
3 Outer valve spring 4
4 Inner valve spring 4
5 Intake valve 2
6 Exhaust valve 2
7 Valve stem seal 4
8 Lower spring seat 4
9 Valve guide 4
For installation, reverse the removal 
procedure.
5683472 1
834721
8 3 4 7 2
1
8 3 4 7 2 1
M
E
M
E
New
New
New
New
9
9
9
9
M
M 
						

							VALVES AND VALVE SPRINGS
5-35
EAS24280REMOVING 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 5-37.



 





 
 








 
 



 
 



 



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”.
        
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”
Outer valve spring “2”
Inner valve spring “3”
Valve “4”
Valve stem seal “5”
Lower spring seat “6”
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”
 
Valve-stem-to-valve-guide 
clearance (intake)
0.010–0.037 mm (0.0004–0.0015 
in)
Limit
0.080 mm (0.0032 in)
Valve-stem-to-valve-guide 
clearance (exhaust)
0.025–0.052 mm (0.0010–0.0020 
in)
Limit
0.100 mm (0.0039 in) 
						

							VALVES AND VALVE SPRINGS
5-36
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.



 





 
 








 
 



 
 



 



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.
          
3. Eliminate:
Carbon deposits
(from the valve face and valve seat)
4. Check:
Valve face
Pitting/wear → Grind the valve face.
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.
 
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
 
Valve margin thickness D (intake)
0.70–1.30 mm (0.0276–0.0512 in)
Limit
0.4 mm (0.02 in)
Valve margin thickness D 
(exhaust)
0.70–1.30 mm (0.0276–0.0512 in)
Limit
0.4 mm (0.02 in) 
						

							VALVES AND VALVE SPRINGS
5-37
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 oil seal.
EAS24300CHECKING 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.



 





 
 



 
 



 
 



 
 



 



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.
          
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.
 
Valve stem runout
0.010 mm (0.0004 in)
 
Valve seat width C (intake)
0.90–1.10 mm (0.0354–0.0433 in)
Limit
2.0 mm (0.08 in)
Valve seat width C (exhaust)
0.90–1.10 mm (0.0354–0.0433 in)
Limit
2.0 mm (0.08 in) 
						

							VALVES AND VALVE SPRINGS
5-38



 





 
 








 
 



 
 



 



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.
          
EAS24310CHECKING 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.
2. Measure:
Compressed valve spring force “a”
Out of specification → Replace the valve 
spring.
 
Inner spring
Free length (intake)
38.26 mm (1.51 in)
Limit
36.26 mm (1.43 in)
Free length (exhaust)
38.26 mm (1.51 in)
Limit
36.26 mm (1.43 in)
Outer spring
Free length (intake)
43.25 mm (1.70 in)
Limit
41.26 mm (1.62 in)
Free length (exhaust)
43.25 mm (1.70 in)
Limit
41.26 mm (1.62 in) 
						

							VALVES AND VALVE SPRINGS
5-39
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”
Lower spring seat “2”
Valve stem seal “3”
Valve “4”
Inner valve spring “5”
Outer valve spring “6”
 
Inner spring
Installed compression spring 
force (intake)
63.00–73.00 N (14.16–16.41 lb) 
(6.42–7.44 kgf)
Installed compression spring 
force (exhaust)
63.00–73.00 N (14.16–16.41 lb) 
(6.42–7.44 kgf)
Installed length (intake)
29.00 mm (1.14 in)
Installed length (exhaust)
29.00 mm (1.14 in)
Outer spring
Installed compression spring 
force (intake)
139.00–161.00 N (31.25–36.19 lb) 
(14.17–16.42 kgf)
Installed compression spring 
force (exhaust)
139.00–161.00 N (31.25–36.19 lb) 
(14.17–16.42 kgf)
Installed length (intake)
31.00 mm (1.22 in)
Installed length (exhaust)
31.00 mm (1.22 in)
b. Installed length
 
Inner spring
Spring tilt (intake)
2.5°/1.7 mm (2.5°/0.067 in)
Spring tilt (exhaust)
2.5°/1.7 mm (2.5°/0.067 in)
Outer spring
Spring tilt (intake)
2.5°/1.9 mm (2.5°/0.075 in)
Spring tilt (exhaust)
2.5°/1.9 mm (2.5°/0.075 in)
 
Recommended lubricant
Molybdenum disulfide oil 
						

							VALVES AND VALVE SPRINGS
5-40
Upper spring seat “7”
(into the cylinder head)
NOTE:
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
5-41
EAS24360
CYLINDERS AND PISTONS
Removing the cylinders and pistons
Order Job/Parts to remove Q’ty Remarks
Cylinder head Refer to “CYLINDER HEADS” on page 5-31.
1 Front cylinder 1
2 Rear cylinder 1
3 Cylinder gasket 2
4 Dowel pin 4
5 Piston pin clip 4
6 Piston pin 2
7Piston 2
8Top ring 2
9 2nd ring 2
10 Oil ring 2
For installation, reverse the removal 
procedure.
1
3
457 8
9
103
4
6557
6
5 8
9
10 2
New
New
New
NewNew
New
E
E
E