Checking The Decompression System; Checking The Valve Lifters; Installing The Camshaft; Installing The Crankcase Cover - Yamaha UMAX Service Manual

6. Calculate:
• Camshaft-to-crankcase clearance
Out of specification → Replace the defective
part(s).
TIP
Calculate the clearance by subtracting the cam-
shaft journal diameter (crankcase side) from the
crankcase hole inside diameter.
Camshaft to crankcase clearance
0.010–0.053 mm
(0.0004–0.0021 in)
7. Calculate:
• Camshaft-to-crankcase cover clearance
Out of specification → Replace the defective
part(s).
TIP
Calculate the clearance by subtracting the cam-
shaft journal diameter (crankcase cover side)
from the crankcase cover hole inside diameter.
Camshaft to crankcase cover
clearance
0.010–0.053 mm
(0.0004–0.0021 in)
8. Check:
• Camshaft drive gear
• Camshaft driven gear
Chips/pitting/roughness/wear → Replace the
defective part(s).

CHECKING THE DECOMPRESSION SYSTEM

1. Check:
• Decompression system
TIP
• Check that the decompression pin "1" projects
from the camshaft.
• Check that the decompression cam "2" and de-
compression pin "1" moves smoothly.
2

CHECKING THE VALVE LIFTERS

1. Check:

INSTALLING THE CAMSHAFT

1. Install:
TIP
Align the punch mark "a" on the camshaft driven
gear "1" with the punch mark "b" on the camshaft
drive gear "2".

INSTALLING THE CRANKCASE COVER

1. Install:
2. Install:
1
5-26
• Valve lifters
Damage/wear → Replace the valve lifter.
• Camshaft
1
a
• Oil seal "1"
New
(into the crankcase cover "2")
Installed depth
0.5–1.5 mm (0.02–0.06 in)
2 1
New
a. Installed depth
• Oil level switch "1"
• Oil level switch lead guide
Oil level switch bolt
10 N·m (1.0 kgf·m, 7.4 lb·ft)
Oil level switch lead guide bolt
10 N·m (1.0 kgf·m, 7.4 lb·ft)
CAMSHAFT
2
b
a