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:

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 loose throttle body joint Improperly adjusted engine idling speed (idle adjusting screw) Improper ...

Checking the front and rear brake pads
The front and rear brake pads must be checked for wear at the intervals specified in the periodic maintenance and lubrication chart. Front brake pads Remove the front brake caliper by removing the bolts. Bolt Brake caliper Lining thickness Check each front br ...

Installing the rear wheel (disc)
1. Install: Rear brake disc NOTE: Tighten the brake disc bolts in stages and in a crisscross pattern. 2. Check: Rear brake disc Refer to "CHECKING THE REAR BRAKE DISC" on page 4-33. 3. Lubricate: Rear wheel axle Contact surface of rear wheel hub and rear wheel Whee ...