Yamaha YZF-R125 Service Manual: Checking the piston rings

1. Measure:

Piston ring side clearance Out of specification Replace the
piston and piston rings as a set.

NOTE:

Before measuring the piston ring side clearance, eliminate any carbon deposits from the piston ring grooves and piston rings.


Checking the piston rings


2. Install:

  • Piston ring (into the cylinder)

NOTE:

Level the piston ring into the cylinder with the piston crown.

Checking the piston rings


a. 40 mm (1.57 in)

3. Measure:

  • Piston ring end gap Out of specification Replace
    the piston ring.

NOTE:

The oil ring expander spacer end gap cannot be measured. If the oil ring rail gap is excessive, replace all three piston rings.


    Checking the cylinder and piston
    1. Check: Piston wall Cylinder wall Vertical scratches Replace the cylinder, and replace the piston and piston rings as a set. 2. Measure: Piston-to-cylinder clearance a. Mea ...

    Checking the piston pin
    1. Check: Piston pin Blue discoloration/grooves  Replace the piston pin and then check the lubrication system. 2. Measure: Piston pin outside diameter "a" Out of specification ...

    Other materials:

    Checking and lubricating the sidestand
    Checking and lubricating the sidestand The operation of the sidestand should be checked before each ride, and the sidestand pivot and metal-to-metal contact surfaces should be lubricated if necessary. WARNING If the sidestand does not move up and down smoothly, have a Yamaha deal ...

    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 ...

    Intake air pressure sensor
    1. Check: Intake air pressure sensor output voltage Out of specification Replace the throttle body. a. Connect the pocket tester (DC 20 V) to the throttle body sensor assembly coupler as shown. Positive tester probe pink/white "1" Negative tester probe gray/black "2" ...

    2021 Copyright www.yam-r125.net |