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:
Storage
Short-term
Always store your motorcycle in a cool,
dry place and, if necessary, protect it
against dust with a porous cover.
NOTICE
Storing the motorcycle in a
poorly ventilated room or covering
it with a tarp, while it is still
wet, will allow water and humidity
to seep in and ...
Checking the transmission
1. Measure:
Main axle runout
(with a centering device and dial gauge "1")
Out of specification Replace
the main axle.
2. Measure:
Drive axle runout
(with a centering device and dial gauge "1")
Out of specification Replace
the drive axle.
3. Check:
Transmiss ...
Checking the relays
Check each switch for continuity with the pocket
tester. If the continuity reading is incorrect, replace
the relay.
1. Disconnect the relay from the wire harness.
2. Connect the pocket tester ( × 1) and battery
(12 V) to the relay terminal as shown.
Check the relay operation.
Out ...