Page 1016 of 3573

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 3573

6A±61
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 1021 of 3573

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 N´m (1.0 Kg´m/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 N´m (1.0 Kg´m/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 1025 of 3573
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
ªCylinder Headº in this manual.
2. Remove crankcase with oil pan (2). Refer to ªOil Pan
and Crankcaseº 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).
Page 1032 of 3573
6A±76
ENGINE MECHANICAL
012RS001
7. Install oil pump assembly (5), refer to ªOil pumpº in
this manual.
8. Install oil strainer and O-ring (4).
9. Install oil pipe and O-ring (3) and tighten the bolts.
Torque: 25 N´m (2.5 Kg´m/18 lb ft)
10. Install crankcase with oil pan (2).
1. Completely remove all residual sealant, lubricant
and moisture from the sealing surfaces. The
surfaces must be perfectly dry.
2. Apply a correct width bead of sealant (TBÐ
1207C or its equivalent) to the contact surfaces of
the oil pan. There must be no gaps in the bead.
3. The crankcase assembly must be installed within
5 minutes after sealant application to prevent
premature hardening of the sealant.
4. Tighten the bolts and nuts to the specified torque.
Torque : 10 N´m (1.0 Kg´m/89 lb in)
013RW010
Legend
(1) Portion Between Bolt Holes
(2) Bolt Hole Portion
11. Install cylinder head assembly, refer to ªCylinder
headº in this manual.
Page 1033 of 3573
6A±77
ENGINE MECHANICAL
Piston and Connecting Rod
Piston, Connecting Rod and Associate Parts
015RW019
Legend
(1) Cylinder Head Assembly
(2) Cylinder Head Gasket
(3) Crankcase with Oil Pan
(4) Oil Pipe and O-Ring
(5) Oil Strainer and O-Ring
(6) Oil Gallery(7) Piston and Connecting Rod Assembly
(8) Piston Ring
(9) Piston Pin
(10) Piston
(11) Connecting Rod
(12) Connecting Rod Cap
Disassembly
1. Remove cylinder head assembly (1). Refer to
ªCylinder Head Removalº in this manual.
2. Remove cylinder head gasket (2).
3. Remove crankcase with oil pan (3). Refer toªOil Pan
and Crankcaseº in this manual.
4. Remove oil pipe and O-ring (4).5. Remove oil strainer and O-ring (5).
6. Remove oil gallery (6).
7. Remove connecting rod cap with connecting rod
lower bearing (12).
8. Remove piston and connecting rod assembly (7).
NOTE: Before removing piston and connecting rod
assembly, measure thrust clearance.
Page 1034 of 3573

6A±78
ENGINE MECHANICAL
015RS031
Remove any ridge or carbon build up from the top
end of the cylinder.
9. Remove the piston rings (8) with a piston ring
expander. Arrange the removed piston rings in the
cylinder number order.
015RS022
10. Remove the piston pin (9) using 5±8840±0551±0
piston pin service set and piston support with a press.
NOTE: Keep the parts removed from each cylinder
separate. All parts must be reinstalled in their original
positions. Heating the connecting rod will permit easy
removal of the piston pin.
015RX001
Legend
(1) Press Ram
(2) Piston
(3) Connecting Rod
(4) Piston Pin
11. Piston (10)
12. Connecting rod (11)
Inspection and Repair
Pistons (10)
Carefully clean away all the carbon adhering to the piston
head and the piston ring grooves.
NOTE: Never use a wire brush to clean the pistons.
Damage will result. Visually check each piston for
cracking, scoring, and other signs of excessive wear. If
any of the above conditions are found, the piston must be
replaced.
Piston Diameter
1. Measure the piston outside diameter with micrometer
at the piston grading position and a right angle to the
piston pin.
Piston grading position (from piston head)
Piston grading position : 43.0 mm (1.6929 in)
Page 1040 of 3573
6A±84
ENGINE MECHANICAL
Tighten the connecting rod cap nuts
Torque : 54 N´m (5.5 Kg´m/40 lb ft)
NOTE: Do not apply engine oil to the bearing back faces.
6. Oil gallery, refer to ªCrankshaft and main bearingº in
this manual.
7. Oil strainer and O-ring.
8. Oil pipe and O-ring.
9. Install crankcase with oil pan, refer to ªOil pan and
Crankcaseº in this manual.
10. Install cylinder head gasket.
11. Install Cylinder head assembly.
Refer to ªCylinder headº in this manual.