Yamaha YZF-R125 Service Manual: Adjusting the drive chain slack
NOTE:
The drive chain slack must be checked at the tightest point on the chain.
| CAUTION: A drive chain that is too tight will overload the engine and other vital parts, and one that is too loose can skip and damage the swingarm or cause an accident. Therefore, keep the drive chain slack within the specified limits. |
1. Stand the vehicle on a level surface.
| WARNING Securely support the vehicle so that there is no danger of it falling over. |
NOTE:
Both wheels should be on the ground without a rider on the vehicle.
2. Turn the rear wheel several times and find the tightest position on the drive chain.
3. Check:
- Drive chain slack "a"
Out of specification
Adjust.
NOTE:
Measure the drive chain slack halfway between the drive axle and the rear wheel axle.
4. Adjust:
- Drive chain slack
a. Loosen the wheel axle nut "1".
b. Loosen both locknuts "2".
c. Turn both adjusting bolts "3" in direction "a" or
"b" until the specified drive chain slack is obtained.
NOTE:
- To maintain the proper wheel alignment, adjust both sides evenly
- Push the rear wheel forward to make sure there is no clearance between the drive chain pullers and the ends of the adjusting bolts.
d. Tighten the wheel axle nut to specification.
e. Tighten the locknuts to specification.
Bleeding the hydraulic brake system
WARNINGBleed the hydraulic brake system whenever:
the system is disassembled.
a brake hose is loosened, disconnected or
replaced.
the brake fluid level is very low.
brak ...
Lubricating the drive chain
The drive chain consists of many interacting
parts. If the drive chain is not maintained properly,
it will wear out quickly. Therefore, the drive
chain should be serviced, especially when the
vehi ...
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:
...
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".
...
Overheating
Engine
1. Clogged coolant passages
Cylinder head and piston
Heavy carbon buildup
2. Engine oil
Incorrect oil level
Incorrect oil viscosity
Inferior oil quality
Cooling system
1. Coolant
Low coolant level
2. Radiator
Damaged or leaking radiator
Faulty radiator cap
...