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:
Checking and lubricating the sidestand
Checking and lubricating the sidestand
The operation of the sidestand should
be checked before each ride, and the
sidestand pivot and metal-to-metal
contact surfaces should be lubricated if
necessary.
WARNING
If the sidestand does not move up
and down smoothly, have a Yamaha
deal ...
Installing the primary drive gear and balancer gears
1. Install:
Balancer driven gear "1"
Lock washer
Balancer drive gear "2"
Primary drive gear
Washer "3"
Balancer driven gear nut
Primary drive gear nut
NOTE:
Align the punch mark "a" in the balancer drive
gear "2" with the punch mark "b" in the balancer
driven gear "1".
...
Adjusting the valve clearance
The following procedure applies to all of the
valves.
NOTE:
Valve clearance adjustment should be made
on a cold engine, at room temperature.
When the valve clearance is to be measured or
adjusted, the piston must be at top dead center
(TDC) on the compression stroke.
1. Remove:
...