Air Injection; Checking The Air Induction System - Yamaha YBR250 2007 Service Manual

AIR INDUCTION SYSTEM

AIR INJECTION

The air induction system bums unburned exhaust
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

CHECKING THE AIR INDUCTION SYSTEM

1. Check:
• hoses
Disconnected
Cracks/damage
• pipe
Cracks/damage
2. Check:
• inner blade valve
• blade valve stopper
Cracks/damage
3. Check:
• air cut-off valve
Cracks/damage
6-36
FI
o C.
Connect properly.
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Replace.
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Replace.
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Replace the blade valve.
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Replace.
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