Yamaha YZF-R125 Service Manual: Incorrect engine idling speed

Yamaha YZF-R125 Service Manual / Troubleshooting / Incorrect engine idling speed

Engine

1. Cylinder and cylinder head

  • Incorrect valve clearance
  • Damaged valve train components

2. Air filter

  • Clogged air filter element

Fuel system

1. Throttle body

  • Damaged or loose throttle body joint
  • Improperly adjusted engine idling speed (idle adjusting screw)
  • Improper throttle cable free play
  • Flooded throttle body
  • Faulty air induction system

Electrical system

1. Battery

  • Discharged battery
  • Faulty battery

2. Spark plug

  • Incorrect spark plug gap
  • Incorrect spark plug heat range
  • Fouled spark plug
  • Worn or damaged electrode
  • Worn or damaged insulator
  • Faulty spark plug cap

3. Ignition coil

  • Broken or shorted primary or secondary coils
  • Faulty spark plug lead
  • Cracked or broken ignition coil

4. Ignition system

  • Faulty ECU
  • Faulty crankshaft position sensor
  • Broken generator rotor woodruff key
    Starting failures
    Engine 1. Cylinder and cylinder head - Loose spark plug - Loose cylinder head or cylinder - Damaged cylinder head gasket - Damaged cylinder gasket - Worn or damaged cylinder - Incorrect valve c ...

    Poor medium-and-high-speed performance
    Refer to "STARTING FAILURES" on page 9-1. Engine 1. Air filter Clogged air filter element Fuel system 1. Fuel pump Faulty fuel pump Faulty gear shifting Shifting is difficult Refer ...

    Other materials:

    Circuit diagram
    4. Main fuse 5. Main switch 9. Battery 25.ECU (engine control unit) 36.License plate light 37.Tail/brake light 44.Headlight relay 46.Pass switch 47.Dimmer switch 51.Headlight (low beam) 52.Auxiliary light 54.Headlight (high beam) 58.Meter light 60.High beam indicator light 64.Ignit ...

    Overheating
    Engine 1. Clogged coolant passages Cylinder head and piston Heavy carbon buildup 2. Engine oil Incorrect oil level Incorrect oil viscosity Inferior oil quality Cooling system 1. Coolant Low coolant level 2. Radiator Damaged or leaking radiator Faulty radiator cap ...

    Installing the rear brake master cylinder
    1. Install: Copper washers "1" Brake hose "2" Rear brake light switch "3" WARNINGProper brake hose routing is essential to insure safe vehicle operation. Refer to "CABLE ROUTING" on page 2-33. CAUTION:When installing the brake hose onto the brake master ...

    2026 Copyright www.yam-r125.net |