Engine

Installing the primary drive gear and balancer gears

~1min read

1. Install:

  • Balancer driven gear "1"
  • Lock washer

  • Balancer drive gear "2"
  • Primary drive gear
  • Washer "3"
  • Balancer driven gear nut
  • Primary drive gear nut

NOTE:

  • Align the punch mark "a" in the balancer drive gear "2" with the punch mark "b" in the balancer driven gear "1".
  • Be sure to install the washer so that its sharp edge "c" is facing the primary drive gear.
Installing the primary drive gear and balancer gears

2. Tighten:

  • Balancer driven gear nut "1"
  • Primary drive gear nut "2"

NOTE:

  • Place the aluminum plate "a" between the balancer drive gear "3" and the balancer driven gear "4", and then tighten the balancer driven gear nut.
  • Place the aluminum plate "b" between the balancer drive gear "3" and the balancer driven gear "4", and then tighten the primary drive gear nut.
Installing the primary drive gear and balancer gears

3. Bend the lock washer tab along a flat side of the nut.

Test yourself

A quick Yamaha YZF-R125 quiz: every answer comes with an explanation and a link to the manual page.