Yamaha YZF-R125 Service Manual: 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. Camshaft sprocket
2. Check:
Timing chain guide (exhaust side)
Damage/wear
Replace.
Checking the cylinder head
1. Eliminate:
Combustion chamber carbon deposits
(with a rounded scraper)
NOTE:
Do not use a sharp instrument to avoid damaging
or scratching:
Spark plug bore threads
Valve seats
...
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 ...
Other materials:
Installing the front brake master cylinder
1. Install:
Brake master cylinder "1"
Brake master cylinder holder "2"
NOTE:
Install the brake master cylinder holder with the
arrow mark "a" pointing forward.
Align the end of the brake master cylinder holder
with the punch mark "b" on the handlebar.
First, tighten the front bo ...
Checking the rocker arms and rocker arm shafts
The following procedure applies to all of the
rocker arms and rocker arm shafts.
1. Check:
Rocker arm
Damage/wear Replace.
2. Check:
Rocker arm shaft
Blue discoloration/excessive wear/pitting/
scratches Replace or
check the lubrication
system.
3. Measure:
Rocke ...
Checking the rear brake hose
1. Check:
Brake hoses "1"
Cracks/damage/wear
Replace.
2. Check:
Brake hose holder "2"
Loose connection Tighten the
holder bolt.
Loose or open holder Fasten
properly.
3. Hold the vehicle upright and apply the rear
brake several times.
4. Check:
Brake ho ...