Yamaha YZF-R125 Service Manual: Removing the piston
1. Remove:
-
Piston pin clips "1"
-
Piston pin "2"
-
Piston "3"
| CAUTION: Do not use a hammer to drive the piston pin out. |
NOTE:
-
Before removing the piston pin clip, cover the crankcase opening with a clean rag to prevent the piston pin clip from falling into the crankcase.
-
Before removing the piston pin, deburr the piston pin clip groove and the piston pin bore area.
If both areas are deburred and the piston pin is still difficult to remove, remove it with the piston pin puller set "4".
2. Remove:
-
Top ring
-
2nd ring
-
Oil ring
NOTE:
When removing a piston ring, open the end gap with your fingers and lift the other side of the ring over the piston crown.
Checking the cylinder and piston
1. Check:
Piston wall
Cylinder wall
Vertical scratches Replace the
cylinder,
and replace the piston and piston rings as a
set.
2. Measure:
Piston-to-cylinder clearance
a. Mea ...
Other materials:
Installing the swingarm
1. Lubricate:
Bearings
Spacers
Dust covers
Pivot shaft
2. Install:
Bearings "1"
2. Swingarm
A. Left side
B. Right side
3. Install:
Swingarm adjusting collar "1"
Swingarm "2"
Pivot shaft
Pivot shaft nut "3"
a. Install, and then fully turn in the swingarm adju ...
Checking the valve seats
The following procedure applies to all of the
valves and valve seats.
1. Eliminate:
Carbon deposits
(from the valve face and valve seat)
2. Check:
Valve seat
Pitting/wear Replace the
cylinder head.
3. Measure:
Valve seat width C "a"
Out of specification Replace
the ...
Intake air pressure sensor
1. Check:
Intake air pressure sensor output voltage
Out of specification Replace the throttle
body.
a. Connect the pocket tester (DC 20 V) to the
throttle body sensor assembly coupler as
shown.
Positive tester probe
pink/white "1"
Negative tester probe
gray/black "2"
...