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 fuel line
1. Remove: Left side panel Refer to "GENERAL CHASSIS" on page 4-1. 2. Lift the fuel tank. (Do not disconnect the fuel hose, drain hose 3. Check: Fuel hose "1" Cracks/damage → Replace. Loose connection Connect properly. 4. Install: Fuel tank Refer to "FUEL TANK" on pa ...

Checking and replacing the rear wheel sprocket
1. Check: Rear wheel sprocket More than 1/4 tooth "a" wear Replace the rear wheel sprocket. Bent teeth Replace the rear wheel sprocket. b. Correct 1. Drive chain roller 2. Rear wheel sprocket 2. Replace: Rear wheel sprocket a. Remove the self-locking nuts and the ...

Checking the shift shaft
1. Check: Shift shaft Bends/damage/wear Replace. Shift shaft spring Damage/wear Replace. Checking the stopper lever 1. Check: Stopper lever Bends/damage Replace. Roller turns roughly Replace the stopper lever. Stopper lever spring Damage/wear Replace. ...