Yamaha YZF-R125 Service Manual: 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.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".
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 ...
Other materials:
Checking the timing chain and timing chain guide
1. Check:
Timing chain
Damage/stiffness Replace the
timing
chain and camshaft sprocket as a set.
2. Check:
Timing chain guide (intake side)
Damage/wear Replace.
Checking the oil strainer
1. Check:
Oil strainer
Damage Replace.
Contaminants Clean with solvent.
...
Checking the brake fluid level
1. Stand the vehicle on a level surface.
NOTE:
Place the vehicle on a suitable stand.
Make sure the vehicle is upright.
2. Check:
Brake fluid level
Below the minimum level mark "a" → Add the
recommended brake fluid to the proper level.
A. Front brake
B. Rear brake
WA ...
Safe Riding
Perform the pre-operation checks each
time you use the vehicle to make sure it
is in safe operating condition. Failure to
inspect or maintain the vehicle properly
increases the possibility of an accident
or equipment damage. See page 4-1
for a list of pre-operation checks.
This motor ...