Yamaha YZF-R125 Service Manual: Installing the primary drive gear and balancer gears
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.
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.
3. Bend the lock washer tab along a flat side of the nut.
Checking the balancer gears and primary drive gear
1. Check:
Balancer drive gear
Balancer driven gear
Cracks/damage/wear Replace.
2. Check:
Primary drive gear
Refer to "CHECKING THE PRIMARY DRIVE
GEAR" on page 5-43.
...
Crankcase
...
Other materials:
Checking the water pump
1. Check:
Water pump housing cover
Water pump housing
Cracks/damage Replace.
Impeller shaft
Cracks/damage/wear Replace.
Bearing
Rough movement Replace.
Radiator outlet hose
Cracks/damage Replace.
...
Air induction system
1. Air induction system hose (air filter case to
reed valve assembly)
2. Air induction system reed valve assembly
3. Air induction system hose (reed valve
assembly to exhaust pipe)
Checking the air induction system
Air injection
The air induction system burns unburned exhaust
gases b ...
Checking the cylinder head breather hose
1. Remove:
Left side panel
Refer to "GENERAL CHASSIS" on page 4-1.
2. Check:
Cylinder head breather hose "1"
Cracks/damage → Replace.
Loose connection → Connect properly.
CAUTION:Make sure the cylinder head
breather hose is
routed correctly.
...