Yamaha WR450F, Owner'S Service Manual

Page: 366 / 794

4 - 23
ENG
AIR INDUCTION SYSTEM
INSPECTION
Air induction system
1. Inspect:
• Air induction hose
Crack/damage
→
Replace.
• Air induction pipe
Crack/damage
→
Replace.
2. Check:
• Operation of air cut valve
Pass air through the pipe and check the
air cut valve for operation.
Does not meet the following condition
→
Replace the air cut valve assembly.
NOTE:
• Blow in air to check for operation.
• When using vacuum, check by the use of the
vacuum/pressure pump gauge set
1
.
CAUTION:
When using vacuum on the pipe
c
, take
care not to exceed the specified value.
a
From air filter
b
To cylinder head (exhaust port)
c
From cylinder head (intake port)
È
Check for induction from air filter.
É
Check for prevention of backflow into air filter.
Ê
Check for prevention of afterburn.
(When throttle is closed at sudden deceleration)
a
to
b
Air passes.
b
to
a
Air does not pass.
a
to
b
Air does not pass when
specified pressure is on
c
.
Vacuum/pressure pump gauge
set:
YB-35956-A/90890-06756
Vacuum specifying pressure:
46.7 ~ 86.7 kPa
(350 ~ 650 mmHg,
13.8 ~ 25.6 inHg)
a
b
È
a
b
É
Ê