Yamaha YZF-R125 Service Manual: Checking the decompression system

Yamaha YZF-R125 Service Manual / Engine / Cylinder head / 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 "2" projects from the camshaft (exhaust cam) as shown in the illustration "A".

d. Move the decompression lever "1" in the direction of the arrow shown and check that the decompression cam does not project from the camshaft (exhaust cam) as shown in the illustration "B".

Checking the decompression system


Checking the decompression system


    Checking the timing chain tensioner
    1. Check: Timing chain tensioner Cracks/damage/rough movement Replace. a. Lightly press the timing chain tensioner rod into the timing chain tensioner housing by hand. NOTE: While pressing the ...

    Installing the cylinder head
    1. Install: Cylinder head NOTE: Pass the timing chain through the timing chain cavity. 2. Tighten: Cylinder head bolts "1" Cylinder head bolts "2" NOTE: Lubricate the cylinder ...

    Other materials:

    Checking the fuel pressure
    1. Check: Pressure regulator operation a. Remove the fuel hose connector cover "1" and disconnect the fuel hose "2" from the fuel pump. CAUTION:Although the fuel has been removed from the fuel tank, be careful when removing the fuel hose, since there may be fuel remaining i ...

    Cleaning the air filter element
    NOTE: There is a check hose "1" at the bottom of the air filter case. If dust and/or water collects in this hose, clean the air filter element and air filter case. 1. Remove: Rider seat Refer to "GENERAL CHASSIS" on page 4-1. 2. Remove: Fuel tank Refer to "FUEL TANK" on page ...

    Checking and lubricating the brake and shift pedals
    Brake pedal Brake pedal Shift pedal Shift pedal The operation of the brake and shift pedals should be checked before each ride, and the pedal pivots should be lubricated if necessary. Recommended lubricant:Lithium-soap-based grease ...

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