Yamaha YZF-R125 Service Manual: Checking the timing chain tensioner
1. Check:
Timing chain tensioner
Cracks/damage/rough movement
Replace.
a. Lightly press the timing chain tensioner rod into the timing chain tensioner housing by hand.
NOTE:
While pressing the timing chain tensioner rod, wind it clockwise with a thin screwdriver "1" until it stops.
b. Remove the screwdriver and slowly release the timing chain tensioner rod.
c. Make sure that the timing chain tensioner rod comes out of the timing chain tensioner housing smoothly. If there is rough movement, replace the timing chain tensioner.
Checking the camshaft sprocket and timing chain guide
1. Check:
Camshaft sprocket
More than 1/4 tooth wear "a" Replace
the
camshaft sprocket, timing chain and crankshaft
as a set.
a. 1/4 tooth
b. Correct
1. Timing chain roller
2. C ...
Checking the decompression system
1. Check:
Decompression system
a. Check the decompression system with the
camshaft sprocket and the decompression
cam installed to the camshaft.
b. Check that the decompression lever "1"
...
Other materials:
Adjusting the clutch cable free play
1. Check:
Clutch cable free play "a"
Out of specification Adjust.
2. Adjust:
Clutch cable free play
a. Pull back the rubber cover "1"
b. Loosen the locknut "2".
c. Turn the adjusting bolt "3" in direction "a" or
"b" until the specified clutch cable free play is
obtained.
...
Installing the exhaust assembly
1. Install:
Exhaust assembly "1"
Exhaust pipe nuts "2"
Exhaust assembly bolts "3" "4"
NOTE:
Do not fully tighten the nuts and bolts.
2. Tighten:
Exhaust pipe nuts "2"
Exhaust assembly bolt "4"
Exhaust assembly bolt "3"
...
Starting failures
Engine
1. Cylinder and cylinder head
- Loose spark plug
- Loose cylinder head or cylinder
- Damaged cylinder head gasket
- Damaged cylinder gasket
- Worn or damaged cylinder
- Incorrect valve clearance
- Improperly sealed valve
- Incorrect valve-to-valve-seat contact
- Incorrect valve timi ...