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:
Checking the starter clutch
1. Check:
Starter clutch rollers "1"
Starter clutch spring caps "2"
Starter clutch springs "3"
Damage/wear Replace the starter
clutch
assembly.
2. Check:
Starter clutch idle gear
Starter clutch gear
Burrs/chips/roughness/wear Replace the
defective part(s).
3. Check:
...
Installing the clutch
1. Install:
Conical spring washer "1"
NOTE:
Install the conical spring washer as shown in the
illustration.
2. Install:
Clutch housing
Thrust washer "1"
NOTE:
Be sure to install the thrust washer so that its
sharp edge "a" is facing away from the clutch
boss.
3. Instal ...
Checking the radiator
1. Check:
Radiator fins
obstruction clean.
Apply compressed air to the rear of the radiator.
Damage repair or replace.
NOTE:
Straighten any flattened fins with a thin, flat-head
screwdriver.
2. Check:
Radiator hoses
Cracks/damage Replace.
3. Measure:
Radiator cap ...