Yamaha YZF-R125 Service Manual: Starting circuit cut-off system operation

Yamaha YZF-R125 Service Manual / Electrical system / Electric starting system / Starting circuit cut-off system operation

If the engine stop switch is set to " " and the main switch is set to
"ON" (both switches are closed), the starter motor can only operate if at least one of the following conditions is met:

  • The transmission is in neutral (the neutral switch is closed).
  • The clutch lever is pulled to the handlebar (the clutch switch is closed) and the sidestand is up (the sidestand switch is closed).

The starting circuit cut-off relay prevents the starter motor from operating when neither of these conditions has been met. In this instance, the starting circuit cut-off relay is open so current cannot reach the starter motor. When at least one of the above conditions has been met, the starting circuit cut-off relay is closed and the engine can be started by pressing the start switch " 
".

Starting circuit cut-off system operation


a. WHEN THE TRANSMISSION IS IN NEUTRAL

b. WHEN CLUTCH LEVER IS PULLED TO THE HANDLEBAR AND THE SIDESTAND IS UP

1. Battery

2. Main fuse

3. Main switch

4. Ignition fuse

5. Engine stop switch

6. Starting circuit cut-off relay

7. Clutch switch

8. Sidestand switch

9. Diode

10.Neutral switch

11.Start switch

12.Starter relay

13.Starter motor

    Circuit diagram
    4. Main fuse 5. Main switch 7. Clutch switch 8. Sidestand switch 9. Battery 10.Starter relay 11.Starter motor 12.Starting circuit cut-off relay 13.Diode 14.Neutral switch 16.Start switch ...

    Troubleshooting
    The starter motor fails to turn. NOTE: Before troubleshooting, remove the following part(s): 1. Seats 2. Fuel tank 3. Left lower side cowling 4. Left upper side cowling ...

    Other materials:

    Installing the steering head
    1. Lubricate: Upper bearing Lower bearing Bearing races 2. Install: Lower ring nut Rubber washer Upper ring nut Lock washer Refer to "CHECKING AND ADJUSTING THE STEERING HEAD" on page 3-22. 3. Install: Upper bracket Steering stem nut NOTE: Temporarily tighten t ...

    Installing the shift forks and shift drum assembly
    1. Install: Shift fork-L "1" Shift fork-C "2" Shift fork-R "3" Shift drum assembly "4" Springs Shift fork guide bar "5" NOTE: The embossed marks on the shift forks should face towards the right side of the engine and be in the following sequence: "R", "C", "L". 2. Check: Tr ...

    Checking the starter motor operation
    1. Check: Starter motor operation Does not operate → Perform the electric starting system troubleshooting, starting with step 4. Refer to "TROUBLESHOOTING" on page 8-9. a. Connect the positive battery terminal "1" and starter motor lead "2" with a jumper lead "3". W ...

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