Kawasaki J300 - Service manual > Valves

Valve Clearance Inspection

• Refer to the Valve Clearance Inspection in the Periodic Maintenance chapter.

Valve Clearance Adjustment

• Refer to the Valve Clearance Adjustment in the Periodic Maintenance chapter.

Valve Removal

• Remove:
  Cylinder Head (see Cylinder Head Removal)
  Rocker Arms and Rocker Shafts (see Rocker Arm Removal)
  Camshaft (see Camshaft Removal)
• Using the valve spring compressor assembly [A] and adapter [B], remove the valve.

Special Tools -
 Valve Spring Compressor Assembly: 57001 -241
 Valve Spring Compressor Adapter, 22: 57001-1202

NOTE

• Mark and record the valve locations so that they can be installed in their original positions to keep the valve clearance unchanged.

Valve Installation

• Replace the oil seal with a new one.
• Apply a thin coat of molybdenum disulfide grease to the valve stem before valve installation.
• Install the spring so that the closed coil end faces downwards.

  Valve Stem [A]
  Spring Seat [B]
  Oil Seal [C]
  Closed Coil Ends [D]
  Valve Spring (Outer) [E]
  Valve Spring (Inner) [F]
  Retainer [G]
  Split Keepers [H]

Valve Seat Inspection

• Remove the valve (see Valve Removal).
• Check the valve seating surface [A] between the valve [B] and valve seat [C].
  • Measure the outside diameter [D] of the seating pattern on the valve seat.

  If the outside diameter is too large or too small, repair the seat (see Valve Seat Repair).

Valve Seating Surface Outside Diameter
 Standard:
  Exhaust 23.5 - 23.7 mm (0.925 - 0.933 in.)
  Intake 29.3 - 29.5 mm (1.15 - 1.16 in.)

• Measure the seat width [E] of the portion where there is no build-up carbon (white portion) of the valve seat with a vernier caliper.

  Good [F]

If the width is too wide [G], too narrow [H] or uneven [J], repair the seat (see Valve Seat Repair).

Valve Seating Surface Width
 Standard:
  Exhaust 1.2 mm (0.047 in.)
  Intake 1.2 mm (0.047 in.)

Valve Seat Repair

• Repair the valve seat with the valve seat cutters [A].

Special Tools -
 Valve Seat Cutter Holder Bar [B]: 57001 -1128
 Valve Seat Cutter Holder, 5 [C]: 57001-1208

[For Exhaust Valve Seat]
 Valve Seat Cutter, 45º - 24.5: 57001-1113
 Valve Seat Cutter, 32º - 25: 57001-1118
 Valve Seat Cutter, 60º - 25: 57001-1328
[For Intake Valve Seat]
 Valve Seat Cutter, 45º - 30: 57001-1187
 Valve Seat Cutter, 32º - 30: 57001-1120
 Valve Seat Cutter, 60º - 30: 57001-1123

If the manufacturer's instructions are not available, use the following procedure.

Seat Cutter Operation Care

1. This valve seat cutter is developed to grind the valve for repair. Therefore the cutter must not be used for other purposes than seat repair.

2. Do not drop or shock the valve seat cutter, or the diamond particles may fall off.

3. Do not fail to apply engine oil to the valve seat cutter before grinding the seat surface. Also wash off ground particles sticking to the cutter with washing oil.

NOTE

• Do not use a wire brush to remove the metal particles from the cutter. It will take off the diamond particles.

4. Setting the valve seat cutter holder in position, operate the cutter in one hand. Do not apply too much force to the diamond portion.

NOTE

• Prior to grinding, apply engine oil to the cutter and during the operation, wash off any ground particles sticking to the cutter with washing oil.

5. After use, wash it with washing oil and apply thin layer of engine oil before storing.

Marks Stamped on the Cutter

The marks stamped on the back of the cutter [A] represent the following.

60º ........................... Cutter angle [B]
37.5........................ Outer diameter of cutter [C]

Operating Procedures

• Clean the seat area carefully.
• Coat the seat with machinist's dye.
• Fit a 45º cutter into the holder and slide it into the valve guide.
• Press down lightly on the handle and turn it right or left.

  Grind the seating surface only until it is smooth.

NOTICE Do not grind the seat too much. Overgrinding will reduce valve clearance by sinking the valve into the head. If the valve sinks too far into the head, it will be impossible to adjust the clearance, and the cylinder head must be replaced.

• Measure the outside diameter of the seating surface with a vernier caliper.

  If the outside diameter of the seating surface is too small, repeat the 45º grind until the diameter is within the specified range.

  Widened Width [A] of engagement by machining with 45º cutter
  Ground Volume [B] by 32º cutter 32º [C]
  Correct Width [D]
  Ground Volume [E] by 60º cutter 60º [F]

• Measure the outside diameter of the seating surface with a vernier caliper.

  If the outside diameter of the seating surface is too small, repeat the 45º grind [A] until the diameter is within the specified range.

  Original Seating Surface [B]

NOTE

• Remove all pittings of flaws from 45º ground surface.
• After grinding with 45º cutter, apply thin coat of machinist's dye to seating surface. This makes seating surface distinct and 32º and 60º grinding operation easier.

If the outside diameter [A] of the seating surface is too large, make the 32º grind described below.

If the outside diameter of the seating surface is within the specified range, measure the seat width as described below.

• Grind the seat at a 32º angle [B] until the seat outside diameter is within the specified range.
  • To make the 32º grind, fit a 32º cutter into the holder, and slide it into the valve guide.
  • Turn the holder one turn at a time while pressing down very lightly. Check the seat after each turn.

NOTICE The 32º cutter removes material very quickly.

Check the seat outside diameter frequently to prevent overgrinding.

• After making the 32º grind, return to the seat outside diameter measurement step above.

• To measure the seat width, use a vernier caliper to measure the width of the 45º angle portion of the seat at several places around the seat.

  If the seat width is too narrow, repeat the 45º grind until the seat is slightly too wide, and then return to the seat outside diameter measurement step above.

If the seat width is too wide, make the 60º [A] grind described below.

If the seat width is within the specified range, lap the valve to the seat as described below.

• Grind the seat at a 60º angle until the seat width is within the specified range.
  • To make the 60º grind, fit 60º cutter into the holder, and slide it into the valve guide.
  • Turn the holder, while pressing down lightly.
  • After making the 60º grind, return to the seat width measurement step above.

    Correct Width [B]

• Lap the valve to the valve seat, once the seat width and outside diameter are within the ranges specified above.
  • Put a little coarse grinding compound on the face of the valve in a number of places around the valve head.
  • Spin the valve against the seat until the grinding compound produces a smooth, matched surface on both the seat and the valve.
  • Repeat the process with a fine grinding compound.

    Lapper [A]
    Valve Seat [B]
    Valve [C]

• The seating area should be marked about in the middle of the valve face.

  If the seat area is not in the right place on the valve, check to be sure the valve is the correct part. If it is, it may have been refaced too much; replace it.

• Be sure to remove all grinding compound before assembly.
• When the engine is assembled, be sure to adjust the valve clearance (see Valve Clearance Inspection in the Periodic Maintenance chapter).

Valves

See also: