Yamaha YZF-R125 Service Manual: Poor medium-and-high-speed performance
Refer to "STARTING FAILURES" on page 9-1.
Engine
1. Air filter
- Clogged air filter element
Fuel system
1. Fuel pump
- Faulty fuel pump
Faulty gear shifting
Shifting is difficult
Refer to "Clutch drags".
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 loo ...
Shift pedal does not move
Shift shaft
Improperly adjusted shift rod
Bent shift shaft
Shift drum and shift forks
Foreign object in a shift drum groove
Seized shift fork
Bent shift fork guide bar
Transmission ...
Other materials:
General chassis
Installing the air filter case
1. Install:
Air filter case joint clamp
NOTE:
Align the projection "a" on the air filter case with
the slot "b" in the air filter case joint clamp.
...
Checking the cylinder and piston
1. Check:
Piston wall
Cylinder wall
Vertical scratches Replace the
cylinder,
and replace the piston and piston rings as a
set.
2. Measure:
Piston-to-cylinder clearance
a. Measure cylinder bore "C" with the cylinder
bore gauge.
NOTE:
Measure cylinder bore "C" by takin ...
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 ...