4-Year Checks; Checking The Starter Generator Brushes And Commutator (Yum1A/Yum2A); Checking The Cylinder Head Bolts (Yum1A/Yum2A); Adjusting The Valve Clearance (Yum1A/Yum2A) - Yamaha UMAX Service Manual

4-YEAR CHECKS

CHECKING THE STARTER GENERATOR
BRUSHES AND COMMUTATOR (YUM1A/
YUM2A)
1. Check:
• Brush length
• Commutator diameter
Refer to "CHECKING THE STARTER GEN-
ERATOR" on page 5-19.
CHECKING THE CYLINDER HEAD BOLTS
(YUM1A/YUM2A)
1. Check:
• Cylinder head bolts
Loosen → Tighten.
Refer to "INSTALLING THE CYLINDER
HEAD" on page 5-9.
ADJUSTING THE VALVE CLEARANCE
(YUM1A/YUM2A)
TIP
• Valve clearance adjustment should be made
on a cold engine, at room temperature.
• When the valve clearance is to be measured or
adjusted, the piston must be at top dead center
(TDC) on the compression stroke.
1. Remove:
• Seat frames (driver and passenger)
Refer to "GENERAL CHASSIS (1)" on page
4-1.
2. Lift up the cargo bed (YUM2A).
3. Remove:
• Spark plug
• Cylinder head cover
Refer to "CYLINDER HEAD AND ROCKER
ARMS" on page 5-6.
4. Measure:
• Valve clearance
Out of specification → Adjust.
Valve clearance cold
Intake and exhaust
0.05–0.09 mm (0.0020–0.0035 in)
a. Carefully insert a dial gauge through the
spark plug hole until it touches the top of
the piston.
b. Rotate the primary sheave assembly until
the dial indicator reaches its highest posi-
tion.
c. Paint alignment marks "a" on the primary
sheave assembly and crankcase.
d. Check that the intake and exhaust rocker
arms "1" are loose.
1
e. If the intake and exhaust rocker arms are
not loose, rotate the primary sheave as-
sembly one full turn counterclockwise.
f. Measure the valve clearance with a thick-
ness gauge "1".
Thickness gauge
90890-03180
Feeler gauge set
YU-26900-9
5. Adjust:
• Valve clearance
a. Loosen the locknut.
b. Turn the adjuster with the tappet adjusting
tool "1" in or out until the specified clear-
ance is obtained.
3-20
4-YEAR CHECKS
a
1