Yamaha YZF-R125 Service Manual: 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:
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 ...
Adjusting the drive chain slack
NOTE:
The drive chain slack must be checked at the
tightest point on the chain.
CAUTION:A drive chain that is too tight will
overload
the engine and other vital parts, and one that
is too loose can skip and damage the swingarm
or cause an accident. Therefore, keep
the drive ...
Installing the water pump
1. Install:
Water pump assembly "1"
O-rings "2"
NOTE:
Align the projection "a" on the impeller shaft
with the slit "b" on the camshaft sprocket bolt.
Lubricate the O-rings with a thin coat of lithiumsoap-
based grease.
2. Fill:
Cooling system
(with the specified amou ...