Yamaha YZF-R125 Service Manual: Checking the thermostat

1. Check:

  • Thermostat Does not open at 80.5-83.5 C (176.9-182.3 F)  Replace.

a. Suspend the thermostat "1" in a container "2" filled with water.

b. Slowly heat the water "3".

c. Place a thermometer "4" in the water.

d. While stirring the water, observe the thermostat and thermometer's indicated temperature.

Checking the thermostat


A. Fully closed

B. Fully open

NOTE:

If the accuracy of the thermostat is in doubt, replace it. A faulty thermostat could cause serious overheating or overcooling.

2. Check:

  • Thermostat cover Cracks/damage Replace.

3. Check:

  • Radiator inlet hose Cracks/damage  Replace.

    Thermostat
    ...

    Installing the thermostat
    1. Install: Thermostat NOTE: Install the thermostat with its breather hole "a" facing up. 2. Install: Copper washer Coolant temperature sensor CAUTION:Use extreme care when ...

    Other materials:

    Storage
    Short-term Always store your motorcycle in a cool, dry place and, if necessary, protect it against dust with a porous cover. NOTICE Storing the motorcycle in a poorly ventilated room or covering it with a tarp, while it is still wet, will allow water and humidity to seep in and ...

    Removing the cylinder head
    1. Align: "I" mark "a" on the generator rotor (with the stationary pointer "b" on the generator cover) a. Turn the crankshaft counterclockwise. b. When the piston is at TDC on the compression stroke, align the "I" mark "c" on the camshaft sprocket with the mark "d" on the cylinder h ...

    Checking the rocker arms and rocker arm shafts
    The following procedure applies to all of the rocker arms and rocker arm shafts. 1. Check: Rocker arm Damage/wear Replace. 2. Check: Rocker arm shaft Blue discoloration/excessive wear/pitting/ scratches  Replace or check the lubrication system. 3. Measure: Rocke ...

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