Yamaha YZF-R125 Service Manual: Engine
- Engine removal
- Cylinder head
- Removing the cylinder head
- Checking the cylinder head
- Checking the camshaft sprocket and timing chain guide
- Checking the timing chain tensioner
- Checking the decompression system
- Installing the cylinder head
- Camshaft
- Checking the camshaft
- Checking the rocker arms and rocker arm shafts
- Installing the camshaft and rocker arms
- Valves and valve springs
- Removing the valves
- Checking the valves and valve guides
- Checking the valve seats
- Checking the valve springs
- Installing the valves
- Cylinder and piston
- Removing the piston
- Checking the cylinder and piston
- Checking the piston rings
- Checking the piston pin
- Installing the piston and cylinder
- Generator and starter clutch
- Removing the generator
- Removing the starter clutch
- Checking the starter clutch
- Installing the starter clutch
- Installing the generator
- Electric starter
- Clutch
- Removing the clutch
- Checking the friction plates
- Checking the clutch plates
- Checking the clutch springs
- Checking the clutch housing
- Checking the clutch boss
- Checking the primary drive gear
- Checking the primary driven gear
- Installing the clutch
- Oil pump
- Shift shaft
- Balancer gear
- Removing the primary drive gear and balancer gears
- Checking the balancer gears and primary drive gear
- Installing the primary drive gear and balancer gears
- Crankcase
- Separating the crankcase
- Checking the crankcase
- Checking the timing chain and timing chain guide
- Checking the bearings and oil seal
- Installing the bearing retainer
- Assembling the crankcase
- Crankshaft
- Transmission
Installing the drive chain
1. Lubricate:
Drive chain
Master link
2. Install:
Drive sprocket
Drive sprocket retainer bolts
3. Install:
Master link
O-rings
Master link plate
Master link clip "1"
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Engine removal
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Other materials:
Checking the radiator fan motor
1. Check:
Radiator fan motor
Faulty/rough movement → Replace.
a. Disconnect the radiator fan motor coupler
from the wire harness.
b. Connect the battery (DC 12 V) as shown.
Positive tester probe →
blue "1"
Negative tester probe →
black "2"
c. Measure ...
Checking the front brake caliper
1. Check:
Brake caliper pistons "1"
Rust/scratches/wear Replace the
brake
caliper assembly.
Brake caliper body "2"
Cracks/damage Replace the brake
caliper
assembly.
Brake fluid delivery passages
(brake caliper body)
Obstruction Blow out with
compressed air.
...
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
...