Yamaha YZF-R125 Service Manual: 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 Replace
    the piston pin.

Checking the piston pin


3. Measure:

  • Piston pin bore diameter "b" Out of specification Replace
    the piston.

Checking the piston pin


4. Calculate:

Piston-pin-to-piston-pin-bore clearance Out of specification Replace the
piston pin and piston as a set.

  • Piston-pin-to-piston-pin-bore clearance = Piston pin bore diameter "b" - Piston pin outside diameter "a"

    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 ...

    Installing the piston and cylinder
    1. Install: Top ring "1" 2nd ring "2" Oil ring expander "3" Lower oil ring rail "4" Upper oil ring rail "5" NOTE: Be sure to install the piston rings so that the manufacturer marks or ...

    Other materials:

    Checking the speed sensor
    1. Check: Speed sensor output voltage Out of specification → Replace. a. Connect the pocket tester (DC 20 V) to the speed sensor coupler (wire harness end) as shown. Positive tester probe gray "1" Negative tester probe gray/black "2" b. Set the main switch to "ON". c. ...

    Outline of the fi system
    The main function of a fuel supply system is to provide fuel to the combustion chamber at the optimum air-fuel ratio in accordance with the engine operating conditions and the atmospheric temperature. In the conventional carburetor system, the air-fuel ratio of the mixture that is supplied t ...

    Installing the exhaust assembly
    1. Install: Exhaust assembly "1" Exhaust pipe nuts "2" Exhaust assembly bolts "3" "4" NOTE: Do not fully tighten the nuts and bolts. 2. Tighten: Exhaust pipe nuts "2" Exhaust assembly bolt "4" Exhaust assembly bolt "3" ...

    2018 Copyright www.yam-r125.net |