Yamaha YZF-R125 Service Manual: Balancer gear

Installing the shift shaft

1. Install: Stopper lever "1" Stopper lever spring "2" NOTE: Install the stopper lever spring as shown in the illustration. Hook the ends of the stopper lever spring onto the stoppe ...

Removing the primary drive gear and balancer gears

1. Loosen: Primary drive gear nut "1" NOTE: Place the aluminum plate "a" between the balancer drive gear "2" and the balancer driven gear "3", and then loosen the primary drive gear nut. ...

Other materials:

Troubleshooting
The starter motor fails to turn. NOTE: Before troubleshooting, remove the following part(s): 1. Seats 2. Fuel tank 3. Left lower side cowling 4. Left upper side cowling ...

Checking the bulbs and bulb sockets
NOTE: Do not check any of the lights that use LEDs. Check each bulb and bulb socket for damage or wear, proper connections, and also for continuity between the terminals. Damage/wear  Repair or replace the bulb, bulb socket or both. Improperly connected Properly connect. No c ...

Faulty clutch
Clutch slips 1. Clutch Improperly assembled clutch Improperly adjusted clutch cable Loose or fatigued clutch spring Worn friction plate Worn clutch plate 2. Engine oil Incorrect oil level Incorrect oil viscosity (low) Deteriorated oil Clutch drags 1. Clutch Unevenly t ...