Yamaha YZF-R125 Owners Manual: Troubleshooting
Although Yamaha motorcycles receive a thorough inspection before shipment from the factory, trouble may occur during operation. Any problem in the fuel, compression, or ignition systems, for example, can cause poor starting and loss of power.
The following troubleshooting charts represent quick and easy procedures for checking these vital systems yourself. However, should your motorcycle require any repair, take it to a Yamaha dealer, whose skilled technicians have the necessary tools, experience, and know-how to service the motorcycle properly.
Use only genuine Yamaha replacement parts. Imitation parts may look like Yamaha parts, but they are often inferior, have a shorter service life and can lead to expensive repair bills.
WARNING
When checking the fuel system, do
not smoke, and make sure there are
no open flames or sparks in the area,
including pilot lights from water
heaters or furnaces. Gasoline or
gasoline vapors can ignite or explode,
causing severe injury or
property damage.
Rear wheel
To remove the rear wheel
WARNING
To avoid injury, securely support the
vehicle so there is no danger of it
falling over.
Loosen the axle nut.
Axle nut
Drive chain slack adjust ...
Troubleshooting charts
Starting problems or poor engine performance
Starting problems or poor engine performance
Engine overheating
WARNING
Do not remove the radiator cap when the engine and radiator are hot.
S ...
Other materials:
Tires
To maximize the performance, durability,
and safe operation of your motorcycle,
note the following points regarding
the specified tires.
Tire air pressure
The tire air pressure should be checked
and, if necessary, adjusted before each
ride.
WARNING
Operation of this vehicle with impro ...
Throttle position sensor
1. Check:
Throttle position sensor
a. Connect the digital circuit tester to the terminals
of the throttle body sensor assembly
coupler as shown.
Positive tester probe →
gray/red terminal "1"
Negative tester probe →
gray/black terminal "2"
b. Measure the throttle pos ...
Special tools
The following special tools are necessary for complete and accurate tune-up
and assembly. Use only
the appropriate special tools as this will help prevent damage caused by the use
of inappropriate tools
or improvised techniques. Special tools, part numbers or both may differ
depending on the ...