Camshaft, Camshaft Chain
the crankshaft sprocket [A].
• Remove
Pull
out
the
camshaft chain [B] downward.
•

Camshaft Chain Installation

the camshaft chain from head side.
• Install
the crankshaft sprocket [A] on the crankshaft [B]
• Install
with their teethes [C] aligned.
• Install the removed parts (see appropriate chapters).

ENGINE TOP END 5-25
Cylinder Head
Cylinder Compression Measurement
NOTE

○Use the battery which is fully charged.
up the engine thoroughly.
• Warm
Stop
the
engine.
• Remove the
plugs (see Spark Plug Replacement in
• the Periodic spark
Maintenance chapter).
the compression gauge [A] and adapter [B] firmly
• Attach
into the spark plug hole.
the starter motor, turn the engine over with the throt• Using
tle 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 × 1.0:
57001-1601
L-Shape Hose [C]: 57001-1606
Cylinder Compression
Usable Range: 875  1 348 kPa (8.93  13.75 kgf/cm²,
127  195.5 psi) @320 r/min (rpm)

the measurement for the other cylinders.
• Repeat
Install
the
plugs (see Spark Plug Replacement in
• the Periodicspark
Maintenance chapter).

○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

Cylinder
compression
is lower 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
Gas leakage around cylinder head

Remedy (Action)
Remove the carbon deposits and
replace damaged parts if necessary.

Replace the gasket with a standard part.
Replace damaged gasket and check
cylinder head warp.
Bad condition of valve seating
Repair if necessary.
Incorrect valve clearance
Adjust the valve clearance.
Incorrect piston/cylinder clearance
Replace the piston and/or cylinder.
Piston seizure
Inspect the cylinder and replace/repair
the cylinder and/or piston as necessary.
Bad condition of piston ring and/or piston Replace the piston and/or the piston
ring grooves
rings.

5-26 ENGINE TOP END
Cylinder Head
Cylinder Head Removal

• Remove:
Thermostat Housing (see Thermostat Removal in the
Cooling System chapter)
Exhaust Pipe (see Exhaust Pipe Removal)
Camshafts (see Camshaft Removal)
Heat Insulation Plate [A] (see Engine Removal in the
Engine Removal/Installation chapter)

a container under the coolant drain bolt [A].
• Place
Drain
the
coolant by removing the coolant drain bolt.
•

• Remove the front camshaft chain guide bolt (upper) [A].

• Remove:
Front Camshaft Chain Guide Bolt (Lower) [A]
Collar
Front Camshaft Chain Guide [B]
Dowel Pin [C]
Rear Camshaft Chain Guide [D]

the M6 and M10 cylinder head bolts as shown
• Loosen
sequence [1  12], and remove them with washers.
• Remove the cylinder head forward.

ENGINE TOP END 5-27
Cylinder Head
Cylinder Head Installation
NOTE

○The camshaft cap is machined with the cylinder head,
so if a new cylinder head is installed, use the cap that
is supplied with the new head.
the dowel pins.
• Install
the cylinder head gasket with a new one.
• Replace
Replace
the
cylinder head bolt washers with new ones.
• Apply molybdenum
oil solution to both sides [A]
• of the cylinder headdisulfide
bolt washers and the threads [B] of
the cylinder head bolts [C].
the M10 cylinder head bolts as shown sequence
• Tighten
[1  10].
Torque - Cylinder Head Bolts (M10):
First: 30 N·m (3.1 kgf·m, 22 ft·lb)
Final: 58 N·m (5.9 kgf·m, 43 ft·lb)

the M6 cylinder head bolts as shown sequence
• Tighten
[11, 12].
Torque - Cylinder Head Bolts (M6): 12 N·m (1.2 kgf·m, 106
in·lb)

the O-ring [A] with a new one.
• Remove
Apply
grease
to the O-ring and install it.
• Install:
• Dowel Pin [B]

•

Rear Camshaft Chain Guide [C]
Front Camshaft Chain Guide [D]
Collar [E]
Tighten:
Torque - Front Camshaft Chain Guide Bolt (Upper) [F]: 25
N·m (2.5 kgf·m, 18 ft·lb)
Front Camshaft Chain Guide Bolt (Lower) [G]: 12
N·m (1.2 kgf·m, 106 in·lb)

• Install the removed parts (see appropriate chapters).

5-28 ENGINE TOP END
Cylinder Head
Cylinder Head Warp Inspection

the cylinder head.
• Clean
a straightedge across the lower surface of the cylinder
• Lay
head at several positions.
a thickness gauge [A] to measure the space between
• Use
the straightedge [B] and the head.
Cylinder Head Warp
–––
Standard:
Service Limit: 0.05 mm (0.0020 in.)

If the cylinder head is warped more than the service limit,
replace 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).

ENGINE TOP END 5-29
Valves
Valve Clearance Inspection

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

Valve Clearance Adjustment

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

Valve Removal

the cylinder head (see Cylinder Head Removal).
• Remove
Remove
valve lifter and shim.
•○Mark andthe
record the valve lifter and shim locations so they

•

can be installed in their original positions.
Using the valve spring compressor assembly, remove the
valve.
Special Tools - Valve Spring Compressor Assembly [A]:
57001-241
Valve Spring Compressor Adapter, 25 [B]:
57001-1019
Valve Spring Compressor Adapter, 24:
57001-1586

Valve Installation
NOTICE
Do not lap the valve to the valve seat, using the
grinding compound. It will come off oxide film
treated surface of the valve.
the oil seal with a new one.
• Replace
Apply
a
thin
coat of molybdenum disulfide grease to the
• valve stem before
valve installation.
Install
the
springs
so
that the closed coil end faces down• wards.
Valve Stem [A]
Oil Seal [B]
Spring Seat [C]
Closed Coil End [D]
Valve Spring [E]:
EX - Purple Paint
IN - White Paint
Retainer [F]
Split Keepers [G]

Valve Guide Removal

• Remove:
Valve (see Valve Removal)
•

Oil Seal
Spring Seat
Heat the area around the valve guide to 120  150°C (248
 302°F), and hammer lightly on the valve guide arbor [A]
to remove the guide from the top of the head.

NOTICE
Do not heat the cylinder head with a torch. This will
warp the cylinder head. Soak the cylinder head in
oil and heat the oil.
Special Tool - Valve Guide Arbor,

4.5: 57001-1331

5-30 ENGINE TOP END
Valves
Valve Guide Installation

engine oil to the valve guide outer surface before
• Apply
installation.
the area around the valve guide hole to about 120 
• Heat
150°C (248  302°F).

NOTICE
Do not heat the cylinder head with a torch. This will
warp the cylinder head. Soak the cylinder head and
heat the oil.
the valve guide driver [A] and washer [B], press
• Using
and insert the valve guide in until the valve guide driver
surface [C] touches the head surface [D].
13.3  13.5 mm (0.52  0.53 in.) [E]
Special Tools - Valve Guide Driver: 57001-1564
Washer: 57001-1612

the valve guide with valve guide reamer [A], even
• Ream
if the old guide is reused.
Special Tool - Valve Guide Reamer,

4.5: 57001-1333

Valve-to-Guide Clearance Measurement (Wobble
Method)
If a small bore gauge is not available, inspect the valve
guide wear by measuring the valve to valve guide clearance
with the wobble method as indicated below.
Insert a new valve [A] into the guide [B] and set a dial
gauge against the stem perpendicular to it as close as
possible to the cylinder head mating surface.
Move the stem back and forth [C] to measure valve/valve
guide clearance.
Repeat the measurement in a direction at a right angle to
the first.
If the reading exceeds the service limit, replace the guide.

•
•
•

ENGINE TOP END 5-31
Valves
NOTE

○The reading is not actual valve/valve guide clearance
because the measuring point is above the guide.
Valve/Valve Guide Clearance (Wobble Method)
Standard:
Exhaust

0.04  0.12 mm (0.0016  0.0047 in.)

Intake

0.03  0.10 mm (0.0012  0.0039 in.)

Service Limit:
Exhaust

0.31 mm (0.012 in.)

Intake

0.30 mm (0.012 in.)

Valve Seat Inspection

the valve (see Valve Removal).
• Remove
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 24.9  25.1 mm (0.980  0.988 in.)
Intake

30.4  30.6 mm (1.197  1.205 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 0.8  1.2 mm (0.031  0.047 in.)
Intake

0.5  1.0 mm (0.020  0.039 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, 4.5 [C]: 57001
-1330
[For Exhaust Valve Seat]
Valve Seat Cutter, 45° -

27.5: 57001-1114

Valve Seat Cutter, 32° -

28: 57001-1119

Valve Seat Cutter, 60° -

25: 57001-1328

[For Intake Valve Seat]
Valve Seat Cutter, 45° -

32: 57001-1115

Valve Seat Cutter, 32° -

33: 57001-1199

Valve Seat Cutter, 60° -

33: 57001-1334

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

5-32 ENGINE TOP END
Valves
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.
60° ........................... 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 45° 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.

ENGINE TOP END 5-33
Valves
the outside diameter of the seating surface with
• Measure
a vernier caliper.
If the outside diameter of the seating surface is too small,
repeat the 45° grind until the diameter is within the specified range.
Widened Width [A] of engagement by machining with
45° cutter
Ground Volume [B] by 32° cutter
32° [C]
Correct Width [D]
Ground Volume [E] by 60° cutter
60° [F]
the outside diameter of the seating surface with
• Measure
a vernier caliper.
If the outside diameter of the seating surface is too small,
repeat the 45° grind [A] until the diameter is within the
specified range.
Original Seating Surface [B]

NOTE

○Remove all pittings of flaws from 45° ground surface.
○After grinding with 45° cutter, apply thin coat of machinist’s dye to seating surface. This makes seating surface
distinct and 32° and 60° grinding operation easier.
○When the valve guide is replaced, be sure to grind with
45° cutter for centering and good contact.
If the outside diameter [A] of the seating surface is too
large, make the 32° 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 32° angle [B] until the seat outside
diameter is within the specified range.
○To make the 32° grind, fit a 32° 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 32° cutter removes material very quickly.
Check the seat outside diameter frequently to prevent overgrinding.

○After making the 32° grind, return to the seat outside di-

•

ameter measurement step above.
To measure the seat width, use a vernier caliper to measure the width of the 45° angle portion of the seat at several places around the seat.
If the seat width is too narrow, repeat the 45° grind until
the seat is slightly too wide, and then return to the seat
outside diameter measurement step above.

5-34 ENGINE TOP END
Valves
If the seat width is too wide, make the 60° [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 60° angle until the seat width is within
the specified range.
○To make the 60° grind, fit 60° cutter into the holder, and
slide it into the valve guide.
○Turn the holder, while pressing down lightly.
○After making the 60° grind, return to the seat width measurement step above.
Correct Width [B]

•

NOTICE
Do not lap the valve to the valve seat, using the
grinding compound. It will come off oxide film
treated surface of the valve.
the engine is assembled, be sure to adjust the valve
• When
clearance (see Valve Clearance Inspection in the Periodic
Maintenance chapter).

ENGINE TOP END 5-35
Valves

5-36 ENGINE TOP END
Throttle Body Assy Holder
Throttle Body Assy Holder Removal

• Remove:
Throttle Body Assy (see Throttle Body Assy Removal in
•

the Fuel System (DFI) chapter)
Throttle Body Assy Holder Clamps [A]
Remove:
Throttle Body Assy Holder Bolts [B]
Throttle Body Assy Holders [C]

Throttle Body Assy Holder Installation

sure to install the new O-rings [A].
• Be
• Apply liquid gasket to any two positions of the new O-ring.
Sealant - Liquid Gasket, TB1211F: 92104-0004

the holders [B] as shown.
• Install
Recession [C]
Tighten
the holder bolts [D] as shown sequence [1  3].
•
Torque - Throttle Body Assy Holder Bolts: 10 N·m (1.0
kgf·m, 89 in·lb)

ENGINE TOP END 5-37
Muffler