Yamaha YZF-R125 Service Manual: Checking the rocker arms and rocker arm shafts

Yamaha YZF-R125 Service Manual / Engine / Camshaft / Checking the rocker arms and rocker arm shafts

The following procedure applies to all of the rocker arms and rocker arm shafts.

1. Check:

Rocker arm Damage/wear Replace.

2. Check:

Rocker arm shaft Blue discoloration/excessive wear/pitting/ scratches Replace or
check the lubrication system.

3. Measure:

Rocker arm inside diameter "a" Out of specification Replace.

Checking the rocker arms and rocker arm shafts

4. Measure:

Rocker arm shaft outside diameter "a" Out of specification Replace.

Checking the rocker arms and rocker arm shafts

5. Calculate:

Rocker-arm-to-rocker-arm-shaft clearance

NOTE:

Calculate the clearance by subtracting the rocker arm shaft outside diameter from the rocker arm inside diameter.

Out of specification Replace the
defective part(s).

Checking the camshaft

1. Check: Camshaft lobes Blue discoloration/pitting/scratches Replace the camshaft. 2. Measure: Camshaft lobe dimensions "a" and "b" Out of specification Replace the cams ...

Installing the camshaft and rocker arms

1. Lubricate: Rocker arms Rocker arm shafts 2. Lubricate: Camshaft 3. Install: Camshaft "1" NOTE: Make sure that the camshaft projections "a" and hole "b" are positioned as s ...

Other materials:

Drive chain slack
The drive chain slack should be checked before each ride and adjusted if necessary. To check the drive chain slack Place the motorcycle on the sidestand. TIP When checking and adjusting the drive chain slack, there should be no weight on the motorcycle. Shift the transmission in ...

Installing the thermostat
1. Install: Thermostat NOTE: Install the thermostat with its breather hole "a" facing up. 2. Install: Copper washer Coolant temperature sensor CAUTION:Use extreme care when handling the coolant temperature sensor. Replace any part that was dropped or subjected to ...

Checking the lean angle sensor
1. Remove: Lean angle sensor 2. Check: Lean angle sensor output voltage Out of specification Replace. a. Connect the lean angle sensor to the wire harness. b. Connect the pocket tester (DC 20 V) to the lean angle sensor coupler as shown. Positive tester probe yellow/green "1" Neg ...