Yamaha YZF-R125 Service Manual: Checking the crankshaft position sensor
1. Disconnect:
- Crankshaft position sensor coupler (from the wire harness)
2. Check:
Crankshaft position sensor resistance
Out of specification
Replace
the crankshaft
position sensor/stator assembly.
a. Connect the pocket tester ( × 100) to the
crankshaft position sensor coupler as shown.
- Positive tester probe
red "1" - Negative tester probe
white "2"
b. Measure the crankshaft position sensor resistance.
Checking the ignition spark gap
1. Check:
Ignition spark gap
Out of specification Perform the
ignition
system troubleshooting, starting with step 5.
Refer to "TROUBLESHOOTING" on page
8-3.
NOTE:
If the ignition spark gap ...
Checking the lean angle sensor
1. Remove:
Lean angle sensor
2. Check:
Lean angle sensor output voltage
Out of specification Replace.
a. Connect the lean angle sensor to the wire
harness.
b. Connect the pocket tester ...
Other materials:
Checking the front brake disc
1. Remove:
Front wheel
Refer to "FRONT WHEEL" on page 4-6.
2. Check:
Brake disc
Damage/galling Replace.
3. Measure:
Brake disc deflection
Out of specification Correct the
brake disc
deflection or replace the brake disc.
a. Place the vehicle on a suitable stand ...
Removing the valves
The following procedure applies to all of the
valves and related components.
NOTE:
Before removing the internal parts of the cylinder
head (e.g., valves, valve springs, valve seats),
make sure the valves properly seal.
1. Check:
Valve sealing
Leakage at the valve seat Check
the valve
...
Checking the clutch boss
1. Check:
Clutch boss splines
Damage/pitting/wear Replace the
clutch
boss.
NOTE:
Pitting on the clutch boss splines will cause erratic
clutch operation.
Checking the pressure plate
1. Check:
Pressure plate
Cracks/damage Replace.
Checking the clutch push lever and short clutch push ...