Yamaha YZF-R125 Service Manual: Checking the ignition timing
NOTE:
Prior to checking the ignition timing, check the wiring connections of the entire ignition system.
Make sure all connections are tight and free of corrosion.
1. Remove:
- Rider seat
- Left lower side cowling Refer to "GENERAL CHASSIS" on page 4-1.
2. Remove:
- Timing mark accessing screw "1"
3. Lift the fuel tank. (Do not disconnect the fuel hose, fuel drain hose, and couplers.) Refer to "FUEL TANK" on page 7-1.
4. Connect:
- Timing light "1"
- Digital tachometer
5. Check:
- Ignition timing
a. Start the engine, warm it up for several minutes,
and then let it run at the specified engine
idling speed. 
b. Check that stationary pointer "a" in the generator cover is within the firing range "b" on the generator rotor.
Incorrect firing range → Check the ignition system.
NOTE:
The ignition timing is not adjustable.
6. Remove:
- Digital tachometer
- Timing light
7. Install:
- Fuel tank Refer to "FUEL TANK" on page 7-1.
8. Install:
- Timing mark accessing screw
(along with the O-ring
)
9. Install:
- Left lower side cowling
- Right side cover
- Rider seat Refer to "GENERAL CHASSIS" on page 4-1.
Checking the spark plug
1. Remove:
Right side cover
Refer to "GENERAL CHASSIS" on page 4-1.
2. Disconnect:
Spark plug cap
3. Remove:
Spark plug
CAUTION:Before removing the spark plug, blow away
...
Measuring the compression pressure
NOTE:
Insufficient compression pressure will result in a
loss of performance.
1. Measure:
Valve clearance
Out of specification →Adjust.
Refer to "ADJUSTING THE VALVE CLEARANCE"
on page ...
Other materials:
Checking the condition of the bulb sockets
The following procedure applies to all of the bulb
sockets.
1. Check:
Bulb socket (for continuity)
(with the pocket tester)
No continuity Replace.
NOTE:
Check each bulb socket for continuity in the
same manner as described in the bulb section,
however, note the following.
a. Install a ...
Checking the front fork
The condition and operation of the front
fork must be checked as follows at the
intervals specified in the periodic maintenance
and lubrication chart.
To check the condition
Check the inner tubes for scratches,
damage and excessive oil leakage.
To check the operation
Place the vehicle ...
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 ...