Yamaha YZF-R125 Service Manual: Checking the fuel pressure
1. Check:
- Pressure regulator operation
a. Remove the fuel hose connector cover "1" and disconnect the fuel hose "2" from the fuel pump.
| CAUTION: Although the fuel has been removed from the fuel tank, be careful when removing the fuel hose, since there may be fuel remaining in it. |
NOTE:
Before removing the hose, place a few rags in the area under where it will be removed.
b. Connect the pressure gauge "3" and fuel
pressure adapter "4".
c. Start the engine.
d. Measure the fuel pressure. 
Faulty Replace the fuel tank (with fuel pump).
e. Connect the fuel hose and install the fuel hose connector cover.
Refer to "INSTALLING THE FUEL HOSE" on page 7-2.
Installing the fuel hose
1. Install:
Fuel hose
Fuel hose connector cover
CAUTION:When installing the fuel hose, make sure
that
it is securely connected, and that the fuel
hose connector cover is in t ...
Throttle body
...
Other materials:
Main switch/steering lock
Main switch/steering lock
The main switch/steering lock controls
the ignition and lighting systems, and is
used to lock the steering. The various
positions are described below.
ON
All electrical circuits are supplied with
power, the meter lighting, taillight, license
plate light and ...
Cleaning the air filter element
NOTE:
There is a check hose "1" at the bottom of the air
filter case. If dust and/or water collects in this
hose, clean the air filter element and air filter
case.
1. Remove:
Rider seat
Refer to "GENERAL CHASSIS" on page 4-1.
2. Remove:
Fuel tank
Refer to "FUEL TANK" on page ...
Checking the piston pin
1. Check:
Piston pin
Blue discoloration/grooves
Replace the
piston pin and then check the lubrication system.
2. Measure:
Piston pin outside diameter "a"
Out of specification Replace
the piston pin.
3. Measure:
Piston pin bore diameter "b"
Out of specifica ...