Maintenance Intervals - Yamaha YZ450FX 2019 Owner's Service Manual

EAM20157

MAINTENANCE INTERVALS

EAM30369
MAINTENANCE INTERVALS
ECA25871
NOTICE
• 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.
Check or mainte-
Item
nance job
Check the valve
clearances
Valve
Inspect
Replace
Inspect
Valve spring
Replace
Inspect
Valve lifter
Replace
Inspect
Camshaft
Replace
Inspect
Camshaft
sprocket
Replace
Inspect
Clean
Piston
Replace
Inspect
Piston ring
Replace
Inspect
Piston pin
Replace
Cylinder head Inspect and clean
Inspect and clean
Cylinder
Replace
MAINTENANCE INTERVALS
Every Every
race third
After
(about (about
break-in
2.5 7.5
hours) hours)
 
3-1
Every
fifth
As
(about
required
12.5
hours)
The engine must be cold.
Check the valve seats and the

valve faces for wear.

Check the free length and the

tilt.


Check for scratches and wear.

• Inspect the camshaft surface.
 • Inspect the decompression
system.

Check for wear on the teeth and

for damage.


Inspect crack.
Inspect carbon deposits and

eliminate them.
Replace the piston, piston pin,
 
piston pin clip, and piston ring
all as a set.
Check the end gap of the piston

ring.
Replace the piston, piston pin,
 
piston pin clip, and piston ring
all as a set.

Replace the piston, piston pin,
 
piston pin clip, and piston ring
all as a set.
• Check the coolant passages
for corrosion.
• Inspect carbon deposits and

eliminate them.
• Check for warpage, and
replace the gasket.

Inspect score marks.

Inspect wear.
Remarks