Yamaha YZ 2019 Series, Owner'S Service Manual

Page: 89 / 398

MAINTENANCE INTERVALS
3-1
EAM20157
MAINTENANCE INTERVALS
EAM30369
MAINTENANCE INTERVALS
NOTICE
ECA25871
• After a break-in or before each race, always check the points shown in “TORQUE-CHECK
POINTS” for tightening torques and retighten them.
• Periodic inspection is essential in making full use of the machine performance. The life of
parts varies significantly according to the environment in which the machine runs (e.g., rain,
dirt, etc.). Therefore, earlier inspection is required by reference to the list below.
Item
Check or
maintenance job
After
break-in
Every
race
(about
2.5
hours)
Every
third
(about
7.5
hours)
Every
fifth
(about
12.5
hours)
As
required
Remarks
Valve
Check the valve
clearances
 
The engine must be cold.
Inspect

Check the valve seats and the
valve faces for wear.
Replace

Valve spring
Inspect

Check the free length and the
tilt.
Replace

Valve lifter
Inspect

Check for scratches and wear.
Replace

Camshaft
Inspect

• Inspect the camshaft surface.
• Inspect the decompression
system.
Replace

Camshaft
sprocket
Inspect

Check for wear on the teeth and
for damage.
Replace

Piston
Inspect

Inspect crack.
Clean

Inspect carbon deposits and
eliminate them.
Replace
 
Replace the piston, piston pin,
piston pin clip, and piston ring
all as a set.
Piston ring
Inspect

Check the end gap of the piston
ring.
Replace
 
Replace the piston, piston pin,
piston pin clip, and piston ring
all as a set.
Piston pin
Inspect

Replace
 
Replace the piston, piston pin,
piston pin clip, and piston ring
all as a set.
Cylinder head Inspect and clean

• Check the coolant passages
for corrosion.
• Inspect carbon deposits and
eliminate them.
• Check for warpage, and
replace the gasket.
Cylinder
Inspect and clean

Inspect score marks.
Replace

Inspect wear.