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"

Checking the ignition timing


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

Checking the ignition timing


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.

Checking the ignition timing


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 crankshaft position sensor
    1. Disconnect: Crankshaft position sensor coupler (from the wire harness) 2. Check: Crankshaft position sensor resistance Out of specification  Replace the crankshaft position sensor/stator assembly. a. Connect the pocket tester ( × 100) to the crankshaft position sensor c ...

    Checking the cooling system
    1. Remove: Side covers Upper side cowlings Refer to "GENERAL CHASSIS" on page 4-1. 2. Check: Radiator "1" Radiator inlet hose "2" Radiator outlet hose "3" Coolant reservoir hose "4" Water pump breather hose "5" Cracks/damage → Replace. Refer to "RADIATOR" on page 6-1 ...

    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 ...

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