Yamaha YZF-R125 Service Manual: Air induction system

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)

Air induction system


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.

    Cracks/damage Replace.


  • Cracks/damage  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".

Checking the air induction system


c. If faulty, replace the air induction system reed valve assembly.

    Installing the throttle body
    1. Install: Throttle body joint clamps NOTE: Align the projections "a" on the throttle body joint with the slot "b" in each throttle body joint clamp. 2. Install: Throttle body joint ...

    Electrical system
    ...

    Other materials:

    Replacing the air filter element and cleaning the check hose
    The air filter element should be replaced at the intervals specified in the periodic maintenance and lubrication chart. Have a Yamaha dealer replace the air filter element more frequently if you are riding in unusually wet or dusty areas. In addition, the air filter check hose must be ...

    Clutch lever
    Clutch lever Clutch lever The clutch lever is located at the left handlebar grip. To disengage the clutch, pull the lever toward the handlebar grip. To engage the clutch, release the lever. The lever should be pulled rapidly and released slowly for smooth clutch operation. Th ...

    Cast wheels
    To maximize the performance, durability, and safe operation of your vehicle, note the following points regarding the specified wheels. The wheel rims should be checked for cracks, bends or warpage before each ride. If any damage is found, have a Yamaha dealer replace the wheel. ...

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