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:

    Checking the decompression system
    1. Check: Decompression system a. Check the decompression system with the camshaft sprocket and the decompression cam installed to the camshaft. b. Check that the decompression lever "1" moves smoothly. c. Without operating the decompression lever, check that the decompression cam " ...

    Introduction
    Welcome to the Yamaha world of motorcycling! As the owner of the YZF-R125, you are benefiting from Yamaha's vast experience and newest technology regarding the design and manufacture of high-quality products, which have earned Yamaha a reputation for dependability. Please take the time to re ...

    Checking the throttle body joint and air filter case joint
    1. Remove: Right lower side cowling Left lower side cowling Refer to "GENERAL CHASSIS" on page 4-1. 2. Check: Throttle body joint "1" Air filter case joint "2" Cracks/damage Replace. 3. Install: Right lower side cowling Left lower side cowling Refer to "GENERAL CHAS ...

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