Yamaha YZF-R125 Service Manual: Removing the cylinder head

Yamaha YZF-R125 Service Manual / Engine / Cylinder head / 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 head.

Removing the cylinder head

2. Loosen:

Camshaft sprocket bolt "1"

NOTE:

While holding the generator rotor nut with a wrench "2", loosen the camshaft sprocket bolt.

Removing the cylinder head

3. Remove:

Camshaft sprocket

NOTE:

To prevent the timing chain from falling into the crankcase, fasten it with a wire "1".

Removing the cylinder head

4. Remove:

Cylinder head

NOTE:

Loosen the bolts in the proper sequence as shown.
Loosen each bolt 1/2 of a turn at a time. After all of the bolts are fully loosened, remove bolts 1, 2, 4, and 6, and then remove the cylinder head with bolts 3 and 5 installed in the bolt holes.

Removing the cylinder head

Cylinder head

* Yamaha bond No. 1215 (Three Bond No. 1215) ...

Checking the cylinder head

1. Eliminate: Combustion chamber carbon deposits (with a rounded scraper) NOTE: Do not use a sharp instrument to avoid damaging or scratching: Spark plug bore threads Valve seats ...

Other materials:

Overheating
Engine 1. Clogged coolant passages Cylinder head and piston Heavy carbon buildup 2. Engine oil Incorrect oil level Incorrect oil viscosity Inferior oil quality Cooling system 1. Coolant Low coolant level 2. Radiator Damaged or leaking radiator Faulty radiator cap ...

Adjusting the brake pedal free play
Adjusting the brake pedal free play Brake pedal free play The brake pedal free play should measure 3.5-4.5 mm (0.14-0.18 in) as shown. Periodically check the brake pedal free play and, if necessary, have a Yamaha dealer adjust it. WARNING An incorrect brake pedal free play in ...

Checking the spark plug
1. Remove: Right side cover Refer to "GENERAL CHASSIS" on page 4-1. 2. Disconnect: Spark plug cap 3. Remove: Spark plug CAUTION:Before removing the spark plug, blow away any dirt accumulated in the spark plug well with compressed air to prevent it from falling ...