Service limit: 0. 10 mm (0. 004 in)

 

When the service limit is exceeded, measure the camshaft journal O.D. and camshaft journal area I.D. of cylinder head and camshaft holders, then compare the measurement with the standard value (page 1-6).

 

• Replace the cylinder head and camshaft holders as a set if the difference from the standard value is larger than that of the camshaft.

 

• Replace the camshaft if the difference from the standard value is larger than that of the cylinder head and camshaft holders.

 

 

10-8

CYLINDER HEAD/VALVES

 

INSTALLATION

 

Be careful not to Rotate the crankshaft counterclockwise, and align the jam the cam chain "T" mark [1] on the flywheel with the index notch [2] on and timing sprocket the left crankcase cover.

 

on the crankshaft when rotating the crankshaft.

 

Be careful not to let	Install the shims [1] in their original locations on the
the shims fall into	valve retainer.
the crankcase.	Lower the rocker arms [2].

 

Each camshaft has an identification mark.

 

• "IN" mark [1]: intake camshaft

• "EX" mark [2]: exhaust camshaft

 

 

Apply molybdenum oil solution to the camshaft [1] lobes and journal surfaces.

 

Apply engine oil to the cam chain [2] whole surface.

 

Install the camshafts into the cylinder head while installing cam chain onto the cam sprockets.

Install the camshaft with its lobes facing up.

 

[1]

 

[2]

 

[2]

 

 

[2]

 

 

[2]

 

[1]

[2]

 

 

[1]

 

[1]

 

10-9

CYLINDER HEAD/VALVES

 

Align the outside index line ("IN" [1] and "EX" [2] marks) on the cam sprockets with the cylinder head top surface as shown.

 

• Check that the punch marks [3] of the cam sprockets is facing up as shown.

 

Install the camshaft holders.

 

Note the correct locations with the identification marks [1] as shown.

 

– "R" mark: right camshaft holder

– "L" mark: left camshaft holder

– "IN" mark: intake side

– "EX" mark: exhaust side

 

Apply engine oil to the camshaft holder mounting bolt [1] threads and seating surface.

 

Install and tighten the camshaft holder mounting bolts to the specified torque.

 

TORQUE:12 N·m (1.2 kgf·m, 9 lbf·ft)

From inside to outside, tighten the bolts in a crisscross pattern in several steps.

 

 

[1]				[2]
	[3]

 

 

[1]

 

[1]

 

Be careful not to let Install the cam chain guide B [1] and bolts [2].

^{the cam chain} Tighten the cam chain guide bolts securely. ^[1] guide bolts fall into

 

the crankcase.

 

[2]

 

 

10-10

CYLINDER HEAD/VALVES

 

Remove the tensioner stopper [1] from the cam chain tensioner lifter.

 

Apply engine oil to a new O-ring [1] and install it to the cam chain tensioner lifter.

 

Install and tighten the cam chain tensioner lifter plug [2] to the specified torque.

 

TORQUE:4.2 N·m (0.4 kgf·m, 3.1 lbf·ft)

 

Inspect the valve clearance (page 3-6). Install the cylinder head cover (page 10-5).

 

ROCKER ARM

• The rocker arm can be serviced with the engine installed in the frame.

 

• The intake and exhaust rocker arm service procedures are the same.

 

REMOVAL/INSTALLATION

 

Remove the camshafts (page 10-6).

 

Remove the bolt [1] and sealing washer [2].

[1]

 

[2]

 

[1]

 

[1]/[2]

 

 

10-11

CYLINDER HEAD/VALVES

 

Remove the rocker arm shaft [1] using a 6 mm bolt [2] while holding the rocker arm [3].

 

Remove the rocker arm.

 

Apply molybdenum oil solution to the rocker arm inner surface, roller surface, slipper surface and rocker arm shaft outer surface.

 

Install the rocker arm and rocker arm shaft.

• The rocker arms are identified by the stamped marks:

– "IN": Intake rocker arm [4]

– "EX": Exhaust rocker arm [5]

 

Install a new sealing washer [1] and bolt [2]. Install the camshafts (page 10-9).

 

 

INSPECTION

 

Inspect the following parts for damage, abnormal wear, deformation, burning or clogs in oil passages.

 

– Rocker arm

– Rocker arm shaft

 

Measure each part and clearance according to CYLINDER HEAD/VALVES SPECIFICATIONS (page 1-6).

 

Replace any part if it is out of service limit.

 

	[3]			[1]		[2]

 

[5]

[4]

[2]

 

[1]

 

10-12

CYLINDER HEAD/VALVES

CYLINDER HEAD

 

 

Be careful not to let the cylinder head bolts and nuts fall into the crankcase.

 

REMOVAL

 

Remove the following:

 

– Engine (page 15-4)

– Camshaft (page 10-6)

 

Remove the cylinder head bolts [1], nuts [2], washers [3] and cylinder head [4].

• Attach a piece of wire to the cam chain to prevent it from falling into the crankcase.

 

• Do not tap the cylinder head too hard and do not damage the mating surface with a screwdriver.

 

Remove the following:

 

– Dowel pins [1]

– Gasket [2]

– Cam chain guide A [3]

 

 

[1]

 

[3]

 

 

[1]

 

 

[2]/[3]

 

[4]

[2]

 

To prevent loss of tension, do not compress the valve springs more than necessary to remove the cotters.

 

Mark all parts during disassembly so they can be installed in their original locations.

 

DISASSEMBLY

 

Remove the following:

 

– Spark plug (page 3-5)

– O2 sensor (page 4-47)

– Rocker arm (page 10-11)

 

Remove the valve spring cotters [1] using the special tools.

 

TOOLS:
[2] Valve spring compressor	07757-0010000
[3] Valve spring compressor
attachment	07959-KM30101

 

Remove the following:

 

– Spring retainer

– Outer/inner valve springs

– Valve

– Stem seal

– Spring seat

 

INSPECTION

 

Inspect the following parts for damage, abnormal wear, deformation, burning or clogs in oil passages.

 

– Cylinder head

– Inner/outer valve springs

– Valves

– Valve guides

– Cam chain guide A

 

Measure each part and clearance according to CYLINDER HEAD/VALVES SPECIFICATIONS (page 1-6).

 

Replace any part if it is out of service limit.

 

[3]

 

[2]

 

 

[1]

 

10-13

CYLINDER HEAD/VALVES

VALVE GUIDE REPLACEMENT

	Refinish the valve seats whenever the valve guides are
	replaced to prevent uneven seating.
	Chill new valve guides in a freezer section of
	refrigerator for about an hour.
Do not use a torch	Heat the cylinder head to 130 – 140°C (266 – 284°F)
to heat the cylinder	with a hot plate or oven. Do not heat the cylinder head
head; it may cause	beyond 150°C (302°F). Use temperature indicator
warping.	sticks, available from welding supply stores, to be sure
	the cylinder head is heated to the proper temperature.
	To avoid burns, wear insulated gloves when handling
	the heated cylinder head.

 

Support the cylinder head and drive out the valve guides from the combustion chamber side of the cylinder head.

TOOL:

 

[1] Valve guide driver 07HMD-ML00101

 

While the cylinder head is still heated, take off a new valve guides [1] from the freezer.

Adjust the valve guide driver to the valve guide height and drive in the valve guide from the camshaft side.

 

TOOL:
[2] Valve guide driver	07743-0020000

 

SPECIFIED HEIGHT:

 

IN/EX: 13.8 – 14.0 mm (0.54 – 0.55 in)

 

Let the cylinder head cool to room temperature.

 

 

[1]

 

Ream a new valve guides.
[1]
TOOL:
[1] Valve guide reamer, 4.5 mm 07HMH-ML00101

• Use cutting oil on the reamer during this operation.

• Take care not to tilt or lean the reamer in the guide while reaming. Otherwise, the valves may be installed slanted, causing oil leakage from the stem seal and improper valve seat contact. This may prevent valve seat refacing

 

• Insert the reamer from the combustion chamber side of the head and always rotate the reamer clockwise.

 

Clean the cylinder head thoroughly to remove any metal particles after reaming and reface the valve seat (page 10-15).

 

 

[1]

 

[2]

 

10-14

CYLINDER HEAD/VALVES