Kawasaki Z400 - Service manual > Cylinder Head

Cylinder Compression Measurement

NOTE

Use the battery which is fully charged.

• Warm up the engine thoroughly.
• Stop the engine.
• Remove: Air Cleaner Housing (see Air Cleaner Housing Removal in the Fuel System (DFI) chapter) Stick Coils (see Stick Coil Removal in the Electrical System chapter) Spark Plugs (see Spark Plug Replacement in the Periodic Maintenance chapter)

• Attach the compression gauge [A] and adapter [B] firmly into the spark plug hole.
• Using the starter motor, turn the mine over with the throttle fully open until the compression gauge stops rising; the compression is the highest reading obtainable.

Special Tools- Compression Gauge, 20 kgf/cm²: 57001-221 Compression Gauge Adapter, M10 x 1.0: 57001 -1 317

Cylinder Compression Usable Range: 1050 ~ 1598 kPa ( 10.71~ 16.30 kgf/cm², 152.3 ~  231.7psi) @500 r/min (rpm)

• Repeat the measurement for the other cylinder.
• Install the spark plugs.

Torque - Spark Plugs: 13 Nm (1.3 kgf*m, 115 In*lb)

The following table should be  consulted if the obtainable compression reading is not within the usable range.

Problem

Cylinder compression is higher than usable range.

Diagnosis

• Carbon accumulation on piston and in combustion chamber possibly due to damaged valve stem oil seal and/or damaged piston oil rings (This may be indicated by white exhaust smoke).
• Incorrect cylinder head gasket thickness

Remedy (Action)

• Remove the carbon deposits and replace damaged parts if necessary.
• Replace the gasket with a standard part.

Problem

Cylinder compression is-lower than usable range.

Diagnosis

• Gas leakage around cylinder head
• Bad condition of valve seating
• Incorrect valve clearance
• Incorrect piston/cylinder clearance
• Pin seizure
• Bad condition of piston ring and/or piston ring grooves

Remedy (Action)

Replace the damaged gasket and check the cylinder head warp.

Repair if necessary.

Adjust the valve clearance.

Replace the piston and/or cylinder.

Inspect the cylinder and replace/repair the cylinder and/or piston as necessary.

Replace the piston and/or the piston rings.

Cylinder Head Removal

• Drain: Want (see Coolant Change in the Periodic Maintenance chapter)
• Remove: Cylinder Head Cover (see Cylinder Head Cover Removal) Camshafts (see Camshaft Removal) Thermostat Housing (see Thermostat Housing Removal in the Cooling System chapter) Throttle Body Assy (see Throttle Body Assy Removal in the Fuel System (DFI) chapter) Exhaust Pipe (see Exhaust Pipe Removal)

• Remove: Front Camshaft Chain Guide [A]
• Disconnect: Water Temperature Sensor Connector [B]

• Support the engine with a suitable jack [A].

• Remove: Front Engine Mounting Bolt [A] (Both Sides) Middle Engine Mounting Bolt [B] (Both Sides) Collars (Left Side) M6 Cylinder Head Bolts [C]

• Remove: M9 Cylinder Head Bolts [A] Cylinder Head

Cylinder Head Installation

NOTE

The camshaft q is machined with the cylinder head, so if a new cylinder head is installed, use the cap that is supplied with the new head.

• Replace the cylinder head gasket [A] with a new one.
• Install: Dowel Pins [B]

• Replace the cylinder head bolt washers with  new ones.
• Apply molybdenum disulfide oil solution to both sides [A] of the cylinder head bolt washers [B] and the threads of the head bolts [C].

• Firstly, tighten the M9 cylinder head bolts temporarily following the specified sequence [1~ 6].
• Next, tighten the M9 cylinder head bolts following the specified sequence [1~ 8].

  Torque -Cylinder Head Bolts  (M9): 20 Nm (2.0 kgf*m, 15 ft-lb)

• Finally, tighten the M9 bolts 120º +-2º  following above specified sequence [1~  6].

• Mark [A] the cylinder head and the bolts so that the bolts can be turned 120º [B] properly.
• Tighten the hexagon bolt by 2 comers.

• The bolts can be tightened by using a torque angle gauge [A]

• Tighten: Toque -Cylinder Head Bolts (Me) [A]: 12 Nm (1.2 kgf*m, 106 in-lb)
• Install the removed parts (see appropriate chapters).

Cylinder Head Warp Inspection

• Clean the cylinder head.
• Lay a straightedge across the lower surface of the cylinder head at several positions.
• Use a thickness gauge [A] to measure the space between the straightedge [B] and the head.

Cylinder Head Warp Standard: - -- Service Limit: 0.05 mm (0.002 in.)

*If the cylinder head is warped more than the service limit, replete it.

*If the cylinder head is warped less than the service limit, repair the head by rubbing the lower surface on emery paper secured to a surface plate (first No. 200, then No.400).

See also: