Yamaha YZF-R125 Service Manual: Jumps out of gear

Shift pedal does not move

Shift shaft Improperly adjusted shift rod Bent shift shaft Shift drum and shift forks Foreign object in a shift drum groove Seized shift fork Bent shift fork guide bar Transmission ...

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 oi ...

Other materials:

Checking the throttle body joint and air filter case joint
1. Remove: Right lower side cowling Left lower side cowling Refer to "GENERAL CHASSIS" on page 4-1. 2. Check: Throttle body joint "1" Air filter case joint "2" Cracks/damage Replace. 3. Install: Right lower side cowling Left lower side cowling Refer to "GENERAL CHAS ...

Adjusting the engine idling speed
NOTE: Prior to adjusting the engine idling speed, the air filter element should be clean, and the engine should have adequate compression. 1. Start the engine and let it warm up for several minutes. 2. Remove: Rider seat Refer to "GENERAL CHASSIS" on page 4-1. 3. Lift the fuel tank. ...

Checking the tires
The following procedure applies to both of the tires. 1. Check: Tire pressure Out of specification Regulate. WARNING The tire pressure should only be checked and regulated when the tire temperature equals the ambient air temperature. The tire pressure must be adjuste ...