Kawasaki Z400 - Service manual > Cylinder, Pistons

Cylinder Removal

• Remove: Cylinder Head (see Cylinder Head Removal) Cylinder [A]

Cylinder  Installation

NOTE

If a new cylinder is wed, use a new piston ring.

• Replace the cylinder gasket [A] and the O-ring [B] with new ones.
• Install: Dowel Pins [C]

• The piston ring openings must be positioned as shown.

  Top Ring [A] Second Ring [B] Upper Oil Ring Steel Rail [C] Oil Ring Expander [D] Lower Oil Ring Steel Rail [E] Dent [fl (Exhaust Side)

Apply molybdenum disulfide oil solution to the cylinder bore, piston rings and piston skirt.

Prepare two auxiliary head bolts [A] with their head cut.

• Install the two bolts diagonally in the crankcase.

• Position the crankshaft so that the piston heads are almost level.
• Install the cylinder [B].

Insert the piston rings with your thumbs.

• Install the removed parts (see appropriate chapters).

Piston Removal

• Remove the cylinder (see Cylinder Removal).
• Place a clean cloth under the pistons and remove the piston pin snap ring [A] from the outside of each piston.
• Remove the piston pins with the piston pin puller [A].

  Center Boll [B] Shell of Piston [C]

Special Tools - Piston Pin Puller Assembly [D]: 57001-910 Piston Pin Puller 57001-1568

• Remove the pistons.
• Carefully spread the ring opening with your thumbs and then push up on the opposite side of the ring [A] to remove it.
• Remove the 3-piece oil ring with your thumbs in the same manner.

Piston installation

Apply molybdenum disulfide oil solution to the oil ring expander, and install the oil ring expander [A] in the bottom piston ring groove so the ends [B] not butt together.

Apply molybdenum disulfide oil solution to the oil ring steel rails, and install the oil ring steel rails, one above the expander and one below it.

• Spread the rail with your thumbs, but only enough to fit the rail over the piston.
• Release the rail into the bottom piston ring groove.

NOTE

The oil ring rails have no "top" or "bottom. "

• Do not mix up the top and second ring.
• Install the top ring [A] so that the "1R" mark [B] faces up.
• Install the second ring [C] so that the "2R" mark [D] faces up.

Apply molybdenum disulfide oil solution to the piston rings.

NOTE

If a new piston is used, use new piston ring.

• Install the piston with its dent mark facing forward.
• Fit a new piston pin snap ring into the side of the piston so that the ring opening [A] does not coincide with the slit [B] of the piston pin hole.

Apply molybdenum disulfide dl solution to the piston pins and piston Journals.

When installing the piston pin snap ring, compress it only enough to install it and no more.

Notice

Do not reuse snap rings, as removal weakens and deforms them. They could fill out and score the cylinder wall.

• Install the cylinder (see Cylinder Installation).

Cylinder Wear inspection

Since them is a difference in cylinder wear in different directions, take a 8idbWde and a front-to- back measurement at each of the two locations (total of four measurements) shown.

*If any of the cylinder inside diameter measurements exceeds the service limit, replace the cylinder.

10 mm (0.39 in.) [A) 60 mm (2.36 in.) [B]

Cylinder Inside Diameter Standard: 69.994 - 70.010 mm (2.7557 - 2.7563 In.) Service Limit:70.09 mm (2.759 In.)

Piston Wear Inspection

• Measure the outside diameter [A] of each piston 5 mm (0.20 in.) [B] up from the bottom of the piston at a right angle to the direction of the piston pin.

*If the measurement is under service limit, replace the piston.

Piston Diameter Standard: 69.967 - 69.982 mm (2.7546 - 2.7552 in.) Service Limit: 69.82 mm (2.749 in.)

Piston Ring, Piston Ring Groove Wear inspection

• Check for uneven groove wear by inspecting the ring seating.

*The rings should fit perfectly parallel to groove surfaces.

If not, replace the piston and all the piston rings.

With the piston rings in their grooves, make several measurements with a thickness gauge [A] to determine piston ring/groove clearance.

Piston Ring/Groove Clearance Standard:

TOP 0.030 - 0.070 mm (0.0012 - 0.0028 In.)

Second 0.020 - 0.060 mm (0.0008 - 0.0024 In.)

Service Limit:

TOP 0.17 mm (0.0067 In.)

Second 0.16 mm (0.0063 In.)

Piston Ring Groove Width inspection

• Measure the piston ring groove width.

Use a vernier caliper at several points around the piston.

Piston Ring Groove Width Standard

Top [A] 0.82 - 0.84 mm (0.0323 - 0.0331 In.)

Second [B] 0.81 - 0.83 mm (0.0319 - 0.0327 in.)

Service Limit:

TOP 0.92 mm (0.0362 in.)

Second 0.91 mm (0.0358 in.)

*If the width of any of the two grooves is wider than the service limit at any point, replace the piston.

Piston Ring Thickness Inspection

Measure the piston ring thickness.

Use the micrometer to measure at several points around the ring

Piston Ring Thickness Standard:

Top [A] 0.77 - 0.79 mm (0.030 - 0.031 In.)

Second [B] 0.77 - 0.79 mm (0.030 - 0.031 In.)

Service Limit:

TOP 0.70 mm (0.028 in.)

Second 0.70 mm (0.028 In.)

*If any of the measurements is less than the service limit on either of the rings, replace all the rings.

NOTE

When using new rings in a used piston, check for uneven groove wear. The rings should fit perfectly parallel to the groove sides. It not, replace the piston.

Piston Ring End Gap inspection

• Place the piston ring [A] inside the cylinder, using the piston to locate the ring squarely in place. Set it close to the bottom of the cylinder, where cylinder wear is low.
• Measure the gap [B] between the ends of the ring with a thickness gauge.

Piston Ring End Gap Standard:

TOP 0.15 - 0.30 mm (0.006 - 0.012 in.)

Second 0.56 - 0.66 mm (0.022 - 0.026 in.)

Service Limit: TOP 0.6 mm (0.02 in.)

Second 1.0 mm (0.04 in.)

*If the end gap of either ring is greater than the service limit, replace all the rings.

Throttle Body Assy Holder Installation

• Replace the O-rings with new ones.

  Tighten: Torque -Throttle Body Assy Holder Bob [A]: 12 N-m (1.2 kgf-m, 106 In-lb)

• Install: Air Cleaner Housing Clamps [B]
• Fit the hole on the clamp to the projections [C] on the throttle body assy holder.

See also: