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.
Test yourself
A quick Yamaha YZF-R125 quiz: every answer comes with an explanation and a link to the manual page.