Yamaha YZF-R125 Service Manual: Changing the engine oil

1. Remove:

• Right bottom cowling
• Right upper side cowling
• Right lower side cowling Refer to "GENERAL CHASSIS" on page 4-1.

2. Start the engine, warm it up for several minutes, and then turn it off.

3. Place a container under the engine oil drain bolt.

4. Install:

• Engine oil drain attachment "1" (Located under the rider seat with the owner's tool kit)

5. Remove:

• Engine oil filler cap (dipstick) "1"
• Engine oil drain plug "2"
• O-ring "3"
• Spring "4"
• Engine oil strainer "5"

6. Drain:

• Engine oil (completely from the crankcase)

7. If the oil filter element is also to be replaced, perform the following procedure.

a. Remove the oil filter element cover "1" and oil filter element "2".

b. Install the new O-ring "3".

c. Install the new oil filter element and the oil filter element cover.

8. Check:

• Engine oil strainer Dirt Clean.

9. Install:

• Engine oil strainer
• Spring
• O-ring


• Engine oil drain plug 

10.Fill:

• Crankcase (with the specified amount of the recommended engine oil)

11.Install:

• Engine oil filler cap

12.Start the engine, warm it up for several minutes, and then turn it off.

13.Check:

• Engine (for engine oil leaks)

14.Check:

• Engine oil level Refer to "CHECKING THE ENGINE OIL LEVEL" on page 3-10.

15.Check:

• Engine oil pressure

a. Slightly loosen the oil check bolt "1".

b. Start the engine and keep it idling until engine oil starts to seep from the oil check bolt. If no engine oil comes out after one minute, turn the engine off so that it will not seize.

c. Check the engine oil passages, the oil filter element and the oil pump for damage or leakage.

Refer to "OIL PUMP" on page 5-47.

d. Start the engine after solving the problem(s) and check the engine oil pressure again.

e. Tighten the oil check bolt to specification.

16.Install:

• Right lower side cowling
• Right upper side cowling
• Right bottom side cowling Refer to "GENERAL CHASSIS" on page 4-1.