Yamaha YZF-R125 Service Manual: Poor medium-and-high-speed performance

Yamaha YZF-R125 Service Manual / Troubleshooting / 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 to "Clutch drags".

    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 loo ...

    Shift pedal does not move
    Shift shaft Improperly adjusted shift rod Bent shift shaft Shift drum and shift forks Foreign object in a shift drum groove Seized shift fork Bent shift fork guide bar Transmission ...

    Other materials:

    Parking
    When parking, stop the engine, and then remove the key from the main switch. WARNING Since the engine and exhaust system can become very hot, park in a place where pedestrians or children are not likely to touch them and be burned. Do not park on a slope or on soft ground, ...

    Removing and installing the cowlings and panel
    Removing and installing the cowlings and panel Cowling A Cowling B Cowling C Cowling D Panel A The cowlings and panel shown need to be removed to perform some of the maintenance jobs described in this chapter. Refer to this section each time a cowling or panel needs to be ...

    Removing the rear brake master cylinder
    NOTE: Before removing the rear brake master cylinder, drain the brake fluid from the entire brake system. 1. Disconnect: Rear brake light switch coupler 2. Loosen: Rear brake light switch "1" 3. Remove: Rear brake master cylinder bolts Rear brake master cylinder 4. Remove: ...

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