Yamaha YZF-R125 Service Manual: Unstable handling

Yamaha YZF-R125 Service Manual / Troubleshooting / Unstable handling

Handlebars

- Bent or improperly installed right handlebar

- Bent or improperly installed left handlebar

1. Steering head components

- Improperly installed upper bracket

- Improperly installed lower bracket (improperly tightened ring nut)

- Bent steering stem

- Damaged ball bearing or bearing race

2. Front fork leg(s)

- Uneven oil levels (both front fork legs)

- Unevenly tensioned fork spring (both front fork legs)

- Broken fork spring

- Bent or damaged inner tube

- Bent or damaged outer tube

3. Swingarm

- Worn bearing

- Bent or damaged swingarm

Rear shock absorber assembly

- Faulty rear shock absorber spring

- Leaking oil

Tire(s)

- Uneven tire pressures (front and rear)

- Incorrect tire pressure

- Uneven tire wear

Wheel(s)

- Incorrect wheel balance

- Deformed cast wheel

- Damaged wheel bearing

- Bent or loose wheel axle

- Excessive wheel runout

Frame

- Bent frame

- Damaged steering head pipe

- Improperly installed bearing race

Faulty front fork legs

Leaking oil - Bent, damaged or rusty inner tube - Cracked or damaged outer tube - Improperly installed oil seal - Damaged oil seal lip - Incorrect oil level (high) - Loose damper rod assembly bo ...

Faulty lighting or signaling system

Headlight does not come on - Wrong headlight bulb - Too many electrical accessories - Hard charging - Incorrect connection - Improperly grounded circuit - Poor contacts (main or light switch) - ...

Other materials:

Removing the generator
1. Remove: Generator rotor nut "1" Washer NOTE: While holding the generator rotor "2" with the sheave holder "3", loosen the generator rotor nut. Do not allow the sheave holder to touch the projection on the generator rotor. 2. Remove: Generator rotor "1" (with the ...

Multi-function display
Multi-function display Multi-function display "RESET/SELECT" button WARNING Be sure to stop the vehicle before making any setting changes to the multi-function display. Changing settings while riding can distract the operator and increase the risk of an accident. The multi- ...

Checking the valve seats
The following procedure applies to all of the valves and valve seats. 1. Eliminate: Carbon deposits (from the valve face and valve seat) 2. Check: Valve seat Pitting/wear Replace the cylinder head. 3. Measure: Valve seat width C "a" Out of specification Replace the ...