Air induction system

1. Air induction system hose (air filter case to reed valve assembly) 2. Air induction system reed valve assembly
3. Air induction system hose (reed valve assembly to exhaust pipe)

Checking the air induction system
Air injection
The air induction system burns 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 C (1112 to 1292 F).
1. Check:
- Hoses Loose connections
Connect
properly.
Replace.
Replace.2. Check:
- Air induction system reed valve assembly operation
a. Blow air into the pipe "1" of the air induction system reed valve assembly and check that it comes out from the pipe "2".
b. Blow air into the pipe "2" of the air induction system reed valve assembly and check that it does not come out from the pipe "1".

c. If faulty, replace the air induction system reed valve assembly.
Test yourself
A quick Yamaha YZF-R125 quiz: every answer comes with an explanation and a link to the manual page.