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:
Checking the front fork
1. Stand the vehicle on a level surface.
WARNINGSecurely support the vehicle so that there
is
no danger of it falling over.
2. Check:
Inner tube
Damage/scratches Replace.
Oil seal
Oil leakage Replace.
3. Hold the vehicle upright and apply the front
brake.
4. Che ...
Fi system
The fuel pump delivers fuel to the fuel injector via the fuel filter. The
pressure regulator maintains the
fuel pressure that is applied to the fuel injector at only 250 kPa (2.50 kg/cm²,
36.3 psi). Accordingly,
when the energizing signal from the ECU energizes the fuel injector, the fuel ...
Installing the crankshaft
1. Install:
Crankshaft "1"
NOTE:
Install the crankshaft with the crankshaft installer
pot "2", crankshaft installer bolt "3", adapter
(M12) "4" and spacer (crankshaft installer) "5".
CAUTION:To avoid scratching the crankshaft and to
ease the installation procedure, lubricate ...