Yamaha TMAX 2020, Service Manual

Page: 99 / 688

3-7
PERIODIC MAINTENANCE
d. To measure the valve clearances of the
other cylinders, starting with cylinder #1 at
TDC, turn the crankshaft clockwise as
specified in the following table.
6. Remove:
• Camshaft
TIP
• Refer to “CAMSHAFTS” on page 5-12.
• When removing the timing chain and cam-
shafts, fasten the timing chain with a wire to re-
trieve it if it falls into the crankcase.
7. Adjust:
• Valve clearance
a. Remove the valve lifter and the valve pad
with a valve lapper.
TIP
• Cover the timing chain opening with a rag to
prevent the valve pad from falling into the
crankcase.
• Make a note of the position of each valve lifter
and valve pad so that they can be installed in
the correct place.
b. Calculate the difference between the spec-
ified valve clearance and the measured
valve clearance.
Example:
Specified valve clearance = 0.15–0.22 mm
(0.0059–0.0087 in)
Measured valve clearance = 0.25 mm
(0.0098 in)
0.25 mm (0.0098 in) - 0.22 mm (0.0087 in)
= 0.03 mm (0.001 in)
c. Check the thickness of the current valve
pad.
TIP
The thickness “a” of each valve pad is marked in
hundredths of millimeters on the side that touch-
es the valve lifter.
Example:
If the valve pad is marked “155”, the pad
thickness is 1.55 mm (0.061 in).
d. Calculate the sum of the values obtained in
steps (b) and (c) to determine the required
valve pad thickness and the valve pad num-
ber.
Example:
1.55 mm (0.061 in) + 0.03 mm (0.001 in) =
1.58 mm (0.062 in)
The valve pad number is 158.
e. Round off the valve pad number according
to the following table, and then select the
suitable valve pad.
A. Front
A. Degrees that the crankshaft is turned
clockwise
B. Cylinder
C. Combustion cycle
Cylinder #2 360

Valve lapper (ø14)
90890-04101
Valve lapping tool (14mm)
YM-A8998
A
G088881
A
B
#1
#2
C
C
0˚ 360˚ 720˚
a
G088885