AIR INDUCTION SYSTEM
7-18
EAS30488
CHECKING THE 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, allow-
ing secondary air to flow into the exhaust port.
The required temperature for burning the un-
burned exhaust gases is approximately 600 to
700 °C (1112 to 1292 °F).
Air cut-off valve
The air cut-off valve is controlled by the signals
from the ECU in accordance with the combus-
tion conditions. Ordinarily, the air cut-off valve
opens to allow the air to flow during idle and
closes to cut-off the flow when the vehicle is be-
ing driven. However, if the coolant temperature
is below the specified value, the air cut-off valve
remains open and allows the air to flow into the
exhaust pipe until the temperature becomes
higher than the specified value.
1. Check:
• Hoses
Loose connections
→
Connect properly.
Cracks/damage
→
Replace.
2. Check:
• Reed valve
• Reed valve stopper
• Reed valve seat
Cracks/damage
→
Replace the reed valve
assembly.
3. Check:
• Air induction system solenoid
Refer to “CHECKING THE AIR INDUCTION
SYSTEM SOLENOID” on page 8-93.
EAS30489
INSTALLING THE AIR INDUCTION SYSTEM
1. Install:
• Reed valve plate “1”
TIP
Align the protection “a” on the cylinder head cov-
er with the hole “b” in the reed valve plate.
2. Install:
• Reed valve assembly
TIP
Install the reed valve assembly so that the open
side turns to the intake side of the engine.
A. From the air filter case
B. To the reed valve
A
B
A. Intake side
a
1
1
b
A
Summary of Contents for YZF-R25
Page 1: ......
Page 2: ......
Page 3: ......
Page 6: ......
Page 8: ......
Page 25: ...BASIC SERVICE INFORMATION 1 16 ...
Page 32: ...SPECIAL TOOLS 1 23 ...
Page 49: ...TIGHTENING TORQUES 2 16 2 6 8 5 4 1 2 6 3 7 2 10 9 A ...
Page 66: ...COOLING SYSTEM DIAGRAMS 2 33 EAS20020 COOLING SYSTEM DIAGRAMS 1 2 3 1 5 4 4 ...
Page 99: ......
Page 128: ...PERIODIC MAINTENANCE 3 29 ...
Page 146: ...GENERAL CHASSIS 5 4 15 1 b b a a 2 ...
Page 200: ...FRONT FORK 4 69 2 b a 1 ...
Page 209: ...SWINGARM AND REAR SHOCK ABSORBER ASSEMBLY 4 78 2 1 1 1 a A B ...
Page 214: ...CHAIN DRIVE 4 83 ...
Page 256: ...CYLINDER AND PISTONS 5 39 1 ...
Page 310: ...TRANSMISSION 5 93 ...
Page 322: ...WATER PUMP 6 11 ...
Page 336: ...THROTTLE BODIES 7 13 c 1 cylinder d 2 cylinder A Left B Right b a d c A B b 1 ...
Page 337: ...THROTTLE BODIES 7 14 ...
Page 338: ...AIR INDUCTION SYSTEM 7 15 EAS20071 AIR INDUCTION SYSTEM 1 2 3 4 5 1 2 ...
Page 342: ...AIR INDUCTION SYSTEM 7 19 ...
Page 345: ......
Page 355: ...ELECTRIC STARTING SYSTEM 8 10 ...
Page 359: ...CHARGING SYSTEM 8 14 ...
Page 371: ...SIGNALING SYSTEM 8 26 ...
Page 417: ...FUEL PUMP SYSTEM 8 72 ...
Page 420: ...ELECTRICAL COMPONENTS 8 75 2 3 4 5 12 11 10 9 8 7 1 6 ...
Page 440: ...ELECTRICAL COMPONENTS 8 95 ...
Page 451: ...SELF DIAGNOSTIC FUNCTION AND DIAGNOSTIC CODE TABLE 9 10 ...
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