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:

Installing the piston and cylinder
1. Install: Top ring "1" 2nd ring "2" Oil ring expander "3" Lower oil ring rail "4" Upper oil ring rail "5" NOTE: Be sure to install the piston rings so that the manufacturer marks or numbers face up. 2. Install: Piston "1" Piston pin "2" Piston pin clips "3" NOTE: ...

Checking the valve seats
The following procedure applies to all of the valves and valve seats. 1. Eliminate: Carbon deposits (from the valve face and valve seat) 2. Check: Valve seat Pitting/wear Replace the cylinder head. 3. Measure: Valve seat width C "a" Out of specification Replace the ...

Checking the transmission
1. Measure: Main axle runout (with a centering device and dial gauge "1") Out of specification Replace the main axle. 2. Measure: Drive axle runout (with a centering device and dial gauge "1") Out of specification Replace the drive axle. 3. Check: Transmiss ...