Yamaha MBK X-MAX 300 2017, Service Manual

Page: 78 / 462

PERIODIC MAINTENANCE
3-7
• Make a note of the position of each valve pad
so that they can be reinstalled in their original
place.
c. Calculate the difference between the
specified valve clearance and the mea-
sured valve clearance.
Example:
Specified valve clearance = 0.06–0.12
mm (0.0024–0.0047 in)
Measured valve clearance = 0.17 mm
(0.0067 in)
0.17 mm (0.0067 in)–0.09 mm (0.0035 in)
= 0.08 mm (0.0031 in)
d. Check the thickness of the current valve
pad.
TIP
The thickness of each valve pad is marked in
hundredths of millimeters on the side that touch-
es the valve cotter.
Example:
If the valve pad is marked “158”, the pad
thickness is 1.58 mm (0.0622 in).
e. Calculate the sum of the values obtained
in steps (b) and (c) to determine the re-
quired valve pad thickness and the valve
pad number.
Example:
1.58 mm (0.0622 in) + 0.05 mm (0.0020
in) = 1.63 mm (0.0641 in)
The valve pad number is 163.
f. Round off the valve pad number according
to the following table, and then select the
suitable valve pad.
TIP
Refer to the following table for the available
valve pads.
Example:
Valve pad number = 163
Rounded value = 165
New valve pad number = 165
g. Install the new valve pad.
TIP
• Lubricate the valve pad with molybdenum di-
sulfide oil.
• Install the valve pad in the correct place.
h. Measure the valve clearance again.
i. If the valve clearance is still out of specifi-
cation, repeat all of the valve clearance
adjustment steps until the specified clear-
ance is obtained.
5. Install:
• All removed parts
TIP
For installation, reverse the removal procedure.
EAS31017
CHECKING THE ENGINE IDLING SPEED
TIP
Prior to checking the engine idling speed, the air
filter element should be clean, and the engine
should have adequate compression.
1. Start the engine and let it warm up for several
minutes.
2. Check:
• Engine idling speed
Out of specification
→
Go to next step.
3. Check:
• ISC (idle speed control) learning value
“00” or “01”
→
Check the intake system.
“02”
→
Clean the ISC (idle speed control) unit
and throttle body.
Refer to “CLEANING THE ISC (IDLE SPEED
CONTROL) UNIT AND THROTTLE BODY”
on page 7-15.
a. Connect the Yamaha diagnostic tool.
Use the diagnostic code number “67”.
Refer to “SELF-DIAGNOSTIC FUNC-
TION AND DIAGNOSTIC CODE TABLE”
on page 9-1.
Last digit Rounded value
1 0
3, 4 5
6, 7 8
9 10
Valve pad range No. 150–350
Valve pad thickness
1.50–3.50 mm
(0.0590–0.1378 in)
Available valve pads
81 thicknesses in 0.025
mm (0.0010 in) incre-
ments
Engine idling speed
1500–1700 r/min
Yamaha diagnostic tool USB
90890-03256
Yamaha diagnostic tool (A/I)
90890-03254