Yamaha YZF-R125 Service Manual: Removing the throttle body
1. Extract the fuel in the fuel tank through the fuel tank filler hole with a pump.
2. Disconnect:
- Fuel hose
| WARNING Cover the fuel hose connections with a cloth when disconnecting them. Residual pressure in the fuel lines could cause fuel to spurt out when removing the hoses. |
NOTE:
- To remove the fuel hose from the fuel injector, slide the fuel hose connector cover "1" on the end of the hose in the direction of the arrow shown, press the two buttons "2" on the sides of the connector, and then remove the hose.
- Remove the fuel hose manually without using any tools.
- Before removing the hose, place a few rags in the area under where it will be removed.
3. Remove:
- Throttle body
| CAUTION: Do not remove the throttle body sensor assembly "1" from the throttle body. |
Checking the fuel injector
1. Check:
- Fuel injector
Damage
Replace.
Throttle body
...
Checking the throttle body
1. Check:
Throttle body
Cracks/damage Replace the
throttle body.
2. Check:
Fuel passages
Obstruction Clean.
a. Wash the throttle body in a petroleum-based
solvent.
Do not us ...
Other materials:
Tachometer
Tachometer
Tachometer
Tachometer red zone
The electric tachometer allows the rider
to monitor the engine speed and keep it
within the ideal power range.
When the key is turned to "ON", the tachometer
needle will sweep once
across the r/min range and then return
to zero r/min ...
Incorrect engine idling speed
Engine
1. Cylinder and cylinder head
Incorrect valve clearance
Damaged valve train components
2. Air filter
Clogged air filter element
Fuel system
1. Throttle body
Damaged or loose throttle body joint
Improperly adjusted engine idling speed (idle
adjusting screw)
Improper ...
Checking the shift drum assembly
1. Check:
Shift drum groove
Damage/scratches/wear Replace
the shift
drum assembly.
Shift drum segment "1"
Damage/wear Replace the
shift drum assembly.
Shift drum bearing "2"
Damage/pitting Replace the
shift drum assembly.
...