Yamaha WR450F 2021, Owner'S Service Manual, Page: 93 / 402

PERIODIC MAINTENANCE
3-3
change the brake fluid.
• Replace the brake hoses every four years and if cracked or damaged.
EAM30334
MAINTENANCE INTERVALS FOR COMPETITION USE
TIP
•
The following schedule is intended as a general guide to maintenance and lubrication. Bear in mind
that such factors as weather, terrain, geographical location, and individual usage will alter the required
maintenance and lubrication intervals. If you are a doubt as to what intervals to follow in maintaining
and lubricating your machine, consult your Yamaha dealer.
•
Periodic inspection is essential in making full use of the machine performance. The service life of the
parts varies substantially 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.
• Items marked with an asterisk should be performed by a Yamaha dealer as they require special tools,
data and technical skills.
No. Item Routine
After
break-in
Every
race
Every
third race
(or 500 km)
Every
fifth race
(or 1000 km)
As
required
1 Engine oil • Replace.
 
2 * Valve
• Check the valve clearances.
 
• Check the valve seats and the
valve stems for wear.

• Replace.

3 * Valve spring
• Check the free length.

• Replace.

4 * Valve lifter
• Check for scratches and wear.

• Replace.

5 * Camshaft
• Inspect the camshaft surface.
• Inspect the decompression sys-
tem.

• Replace.

6 * Camshaft sprocket
• Check for wear on the teeth and
for damage.

• Replace.

7 * Piston
• Inspect crack.
• Inspect carbon deposits and elim-
inate them.
 
• Clean.

• Replace.
(It is recommended that the piston
pin and ring are also replaced at
the same time.)

8 * Piston ring
• Check the ring end gap.

• Replace.
 
9 * Piston pin
• Inspect.

• Replace.

10 * Cylinder head
• Inspect carbon deposits and elim-
inate them.
• Change gasket.

11 * Cylinder
• Inspect score marks.
• Inspect wear.

• Replace.
