Yamaha YZF-R125 Service Manual: Valves and valve springs

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 ...

Removing the valves

The following procedure applies to all of the valves and related components. NOTE: Before removing the internal parts of the cylinder head (e.g., valves, valve springs, valve seats), make sure th ...

Other materials:

Changing the engine oil
1. Remove: Right bottom cowling Right upper side cowling Right lower side cowling Refer to "GENERAL CHASSIS" on page 4-1. 2. Start the engine, warm it up for several minutes, and then turn it off. 3. Place a container under the engine oil drain bolt. 4. Install: Engine oil d ...

Faulty lighting or signaling system
Headlight does not come on - Wrong headlight bulb - Too many electrical accessories - Hard charging - Incorrect connection - Improperly grounded circuit - Poor contacts (main or light switch) - Burnt-out headlight bulb Headlight bulb burnt out - Wrong headlight bulb - Faulty battery - Fau ...

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. 2. Install: Piston ring (into the cylind ...