Page 1014 of 6000

6A–58
ENGINE MECHANICAL
1. Measure the valve stem diameter with a micrometer.
If the valve stem diameter is less than the specified
limit, the valve and the valve guide must be replaced
as a set.
Diameter of Valve Stem
Intake
Standard : 5.977 mm–5.959 mm
(0.2353 in–0.2346 in)
Limit : 5.90 mm (0.2323 in)
Exhaust
Standard : 5.952 mm–5.970 mm
(0.2343 in–0.2350 in)
Limit : 5.90 mm (0.2323 in)
014RS007
2. Measure the inside diameter of the valve guide with a
micrometer. Subtract the measured outer diameter of
the valve stem from the measured inner diameter of
the valve guide. If the value exceeds the specified
limit, the valve and the valve guide must be replaced
as a set.
Inside Diameter of the Vale Guide
Inlet clearance
Standard : 0.023 mm–0.056 mm
(0.0009 in–0.0002 in)
Limit : 0.20 mm (0.00787 in)
Exhaust clearance
Standard : 0.030 mm–0.063 mm
(0.0012 in–0.0025 in)
Limit : 0.20 mm (0.00787 in)
Valve Guide Replacement
1. Using Valve guide replacer: 5–8840–2442–0, drive
out the valve guide from the combustion chamber
side.
014RS008
2. Apply engine oil to the outside of the valve guide.
Using valve guide replacer 5–8840–2442–0, drive in
a new valve guide from the camshaft side, and check
the valve guide height.
Valve guide upper end height: 13.0 mm (0.5118
in)
(Measured from the cylinder head upper face)
014RW046
3. Check the clearance. If the clearance is less than the
specified value, ream the inside diameter of valve
guide. Using a sharp 6 mm reamer, ream the valve
guide to obtain the specified clearance.
Va l v e S e a t
1. Measure the protrusion of the valve stem when a new
valve is installed in the cylinder head. If the protrusion
of the valve stem exceeds the limit, replace the valve
seat insert or the cylinder head assembly.
Protrusion of valve stem
Intake
Standard: 39.32 mm (1.5480 in)
Page 1016 of 6000

6A–60
ENGINE MECHANICAL
6. Check that the valve contact width is correct.
7. Check that the valve seat insert surface is in contact
with the entire circumference of the valve.
014RS014
Valve Seat Insert Replacement
1. Arc weld the rod at several points. Be careful not to
damage the aluminum section.
2. Allow the rod to cool for a few minutes. This will cause
the valve seat to shrink.
3. Strike the rod and pull it out.
014RS015
4. Carefully clean the valve seat press–fit section on the
cylinder head side.
5. Heat the press–fit section with steam or some other
means to cause expansion. Cool the valve seat with
dry ice or some other means.
6. Insert the press–fit section into the valve seat
horizontally.
Standard fitting interference: 0.14 mm–0.09 mm
(0.0055 in–0.0035 in)7. After insertion, use a seat grinder to grind finish the
seating face. Carefully note the seating angle, the
contact width, and the depression.
8. Lap the valve and the seat.
Reassembly
1. Install valve guide (1) to cylinder head. Apply engine
oil to the outside of the valve guide. Using valve guide
replacer 5–8840–2442–0, drive in a new valve guide
from the camshaft side.
2. Install oil controller (3) and spring lower seat (2).
Using oil controller replacer 5–8840–0623–0, drive in
a new oil controller.
014RW058
3. Install valve to valve guide. Before install valve guide
apply engine oil to the outside of the valve stem.
4. Install valve spring to cylinder head. Attach the valve
spring to the lower spring seat. The painted area of
the valve spring should be facing downward.
014RS020
Page 1017 of 6000

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ENGINE MECHANICAL
5. Install lower valve spring seat, valve spring and upper
valve spring seat then put split collars on the upper
spring seat, using the 5–8840–2446–0 valve spring
compressor and 5–8840–2547–0 valve spring
compressor adapter to install the split collars.
014RW042
6. Install tappet with shim.
7. Install camshaft assembly.
Refer to installation procedure for Camshaft in this
manual.
Valve Clearance Adjustments
NOTE: To adjust valve clearance, apply engine oil to the
cam as well as to the adjusting shim (2) with the cylinder
head built on the cylinder block, give a few turns to the
camshaft by means of timing pulley tightening bolt, and
measure valve clearance when the nose of cam is just
opposite to maximum cam lift (1) as shown in illistration
below.
014RW081
Legend
(1) Cam
(2) Shim
(3) Tappet
Valve Clearance Standard Value (cold)
Intake: 0.23 mm–0.33 mm
(0.0091 in–0.0130 in)
Exhaust: 0.25 mm–0.35 mm
(0.0098 in–0.0138 in)
Selection of Adjusting Shim
Shim to be selected = (Thickness of removed shim) +
(Valve clearance measurement – Standard valve)
Based on the above formula, the best suited shim should
be selected from 41 sorts of shim (differently thick at
0.02mm (0.0008 in) intervals from 2.40mm (0.0945 in)
through 3.2mm (0.1260 in) thick). Install the shim and
check valve clearance.
Page 1019 of 6000
6A–63
ENGINE MECHANICAL
Camshaft
Camshaft and Associated Parts
014RW040
Legend
(1) Camshaft Bracket Fixing Bolt
(2) Camshaft Bracket
(3) Camshaft Assembly Intake
(4) Camshaft Assembly Exhaust
(5) Pulley Fixing Bolt(6) Camshaft Drive Gear Pulley
(7) Retainer Fixing Bolt
(8) Retainer
(9) Camshaft Drive Gear
(10) Oil Seal
Disassembly
1. Remove fixing bolt (5) for camshaft drive gear pulley
using the 5–8840–2447–0 universal holder.
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6A–65
ENGINE MECHANICAL
Runout
Limit : 0.1 mm (0.0039 in)
014RW044
4. Measure the camshaft journal oil clearance.
1. Measure the camshaft bracket housing inside
diameter.
NOTE: Tighten camshaft bracket (2) to specified torque
before measuring the camshaft bracket inside diameter.
Torque : 10 Nꞏm (1.0 Kgꞏm/89 lb in)
014RW031
2. Subtract the camshaft outside diameter from the
camshaft bracket housing inside diameter.
Oil Clearance
Standard : 0.027 mm–0.078 mm
(0.0011 in–0.0031 in)
Limit : 0.11 mm (0.0043 in)
014RW037
5. Replace the cylinder head and/or camshaft if the
measured oil clearance exceeds the specified limit.
1. Carefully clean the camshaft journal, the
camshaft bracket, and the cylinder head.
2. Install camshaft assembly and camshaft brackets
(2), tighten twenty bolts (1) on one side bank to
the specified torque.
Torque: 10 Nꞏm (1.0 Kgꞏm/89 lb in)
014RW031
3. Measure the camshaft thrust clearance with a dial
indicator. Replace the camshaft and/or the
cylinder head if the camshaft thrust clearance
exceeds the specified limit.
Camshaft thrust Clearance
Standard : 0.03 mm–0.08 mm
(0.0012 in.–0.0031 in.)
Page 1022 of 6000

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ENGINE MECHANICAL
Limit : 0.12 mm (0.0047 mm)
014RW035
Reassembly
1. Install camshaft drive gear assembly and tighten
three bolts to specified torque.
Torque: 10 Nꞏm (1.0 Kgꞏm/89 lb in)
2. Tighten sub gear setting bolt.
1. Use 5–8840–2443–0 to turn sub gear to right
direction until the M5 bolt hole aligns between
camshaft driven gear and sub gear.
2. Tighten M5 bolt suitable torque for prevent
moving the sub gear.
014RW041
3. Install camshaft assembly and camshaft brackets,
tighten twenty bolts on one side bank to the specified
torque.
1. Apply engine oil to camshaft journal and bearing
surface of camshaft bracket.2. Align timing mark on intake camshaft (one dot for
right bank, two dots for left bank) and exhaust
camshaft (one dot for right bank, two dots for left
bank) to timing mark on camshaft drive gear (one
dot).
014RW020
Legend
(1) Intake Camshaft Timing Gear for Right Bank
(2) Intake Camshaft Timing Gear for Left Bank
(3) Exhaust Camshaft Timing Gear
(4) Discerning Mark
LI: Left Bank Intake
RI: Right Bank Intake
LE: Left Bank Exhaust
RE: Right Bank Exhaust
Page 1024 of 6000
6A–68
ENGINE MECHANICAL
014RW031
4. If the oil seal requires replacement, use the
5–8840–2445–0 to install the oil seal.
014RW034
5. Tighten bolt for camshaft drive gear pulley to the
specified torque using the 5–8840–2447–0 universal
holder.
Torque: 98 Nꞏm (10.0 Kgꞏm/72 lb ft)
014RW060
Page 1025 of 6000
6A–69
ENGINE MECHANICAL
Crankshaft
Crankshaft and Associated Parts
013RW009
Legend
(1) Cylinder Head Assembly
(2) Crankcase with Oil Pan
(3) Oil Pipe and O-Ring
(4) Oil Strainer and O-Ring
(5) Oil Pump Assembly
(6) Cylinder Block Side Bolts
(7) Oil Gallery(8) Piston and Connecting Rod Assembly
(9) Flywheel
(10) Rear Oil Seal Retainer and Oil Seal
(11) Main Bearing Cap
(12) Crankshaft
(13) Main Bearing Cap Fixing Bolts
(14) Oil Gallery Fixing Bolts
Disassembly
1. Remove cylinder head assembly (1). Refer to
“Cylinder Head” in this manual.
2. Remove crankcase with oil pan (2). Refer to “Oil Pan
and Crankcase” in this manual.CAUTION: Take care not to damage or deform the
sealing flange surface of crankcase.
3. Remove oil pipe and O-ring (3).
4. Remove oil strainer and O-ring (4).
5. Remove oil pump assembly (5).
6. Remove crankcase side bolts (6).