Yamaha YZF-R125 Service Manual: Checking the fuel sender
1. Drain the fuel from the fuel tank.
2. Check:
Fuel sender resistance
Out of specification → Replace the fuel
sender.
a. Connect the pocket tester ( 
×
10) to the fuel
sender coupler as shown.
- Positive tester probe
sky blue "1" - Negative tester probe
orange/white "2"
A. Full fuel tank position
B. Empty fuel tank position
b. Measure the fuel sender resistance.
Checking the horn
1. Check:
Horn resistance
Out of specification Replace.
a. Disconnect the horn connectors from the
horn terminals.
b. Connect the pocket tester ( × 1) to the horn
terminals.
Positiv ...
Checking the speed sensor
1. Check:
Speed sensor output voltage
Out of specification → Replace.
a. Connect the pocket tester (DC 20 V) to the
speed sensor coupler (wire harness end) as
shown.
Positive tester pro ...
Other materials:
Measuring the compression pressure
NOTE:
Insufficient compression pressure will result in a
loss of performance.
1. Measure:
Valve clearance
Out of specification →Adjust.
Refer to "ADJUSTING THE VALVE CLEARANCE"
on page 3-3.
2. Start the engine, warm it up for several minutes,
and then turn it off.
3. Remove:
...
Replacing the front brake pads
NOTE:
When replacing the brake pads, it is not necessary
to disconnect the brake hose or disassemble
the brake caliper.
1. Measure:
Brake pad wear limit "a"
Out of specification Replace
the brake
pads as a set.
2. Install:
Brake pad support
Brake pad spring
Brake pads ...
Checking the starter motor
1. Check:
Commutator
Dirt Clean with 600 grit
sandpaper.
2. Measure:
Commutator diameter "a"
Out of specification Replace
the starter
motor.
3. Measure:
Mica undercut "a"
Out of specification Scrape
the mica to the
proper measurement with a hacksaw blade
...