Yamaha FZS1000N, Service Manual

Page: 319 / 394

7-14
VIEW 1. (NO FLOW)
VIEW 2. (FLOW)
AIR INDUCTION SYSTEM
CARB
EAS00507
AIR INDUCTION SYSTEM
AIR INJECTION
The air induction system burns unburned ex-
haust gases by injecting fresh air (secondary
air) into the exhaust port, reducing the emission
of hydrocarbons.
When there is negative pressure at the exhaust
port, the reed valve opens, allowing secondary
air to flow into the exhaust port. The required
temperature for burning the unburned exhaust
gases is approximately 600 to 700
_
C (1112 to
1292
_
F).
EAS00508
AIR CUTOFF VALVE
The air cutoff valve is operated by the intake gas
pressure through the piston valve diaphragm.
Normally, the air cutoff valve is open to allow
fresh air to flow into the exhaust port. During
sudden deceleration (the throttle valve sudden-
ly closes), negative pressure is generated and
the air cutoff valve is closed in order to prevent
after-burning.
Additionally, at high engine speeds and when
the pressure decreases, the air cutoff valve au-
tomatically closes to guard against a loss of per-
formance due to self-EGR.
VIEW 1. (NO FLOW)
When decelerating (the throttle closes), the valve will
close.
VIEW 2. (FLOW)
During normal operation the valve is open.
A From the air cleaner
B To the reed valve
C To the carburetor joint