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:
Installing the piston and cylinder
1. Install:
Top ring "1"
2nd ring "2"
Oil ring expander "3"
Lower oil ring rail "4"
Upper oil ring rail "5"
NOTE:
Be sure to install the piston rings so that the
manufacturer marks or numbers face up.
2. Install:
Piston "1"
Piston pin "2"
Piston pin clips "3"
NOTE:
...
Checking the rear shock absorber assembly
1. Check:
Rear shock absorber rod
Bends/damage Replace the rear
shock
absorber assembly.
Rear shock absorber
Oil leaks Replace the rear
shock absorber
assembly.
Spring
Damage/wear Replace the
rear shock absorber
assembly.
Bushing
Damage/wear Replace the rea ...
Adjusting the engine idling speed
The engine idling speed must be
checked and, if necessary, adjusted as
follows at the intervals specified in the
periodic maintenance and lubrication
chart.
The engine should be warm before
making this adjustment.
Remove panel A.
Check the engine idling speed
and, if necessary, ...