-CRANKSHAFT/
• CONNECTING ROD
10
1.8-2.2kg-m (13.0-15.9f t-lbs)
~1
2.0-2.5kg-m(14.5-18. 1 ft-lbs)
10-0
~
HON DA
~ CB750
~
~
HONDA
CB750
CRANKSHAFT/CONNECTING ROD
TROUBLESHOOTING
10-2
SERVICE INFORMATION
10-2
CRANKSHAFT REMOVAL
10-3
CONNECTING ROD REMOVAL
CRANKPIN OIL CLEARANCE INSPECTION
CONNECTING ROD ASSEMBLY
10-4
10-4
CRANKSHAFT ASSEMBLY
10-8
10-8
10-1
CRANKSHAFT/CONNECTING ROD
~
HOND A
~ CB750
TROUBLESHOOTING
Excessive Noise
1. Cran~shaft
-Excessive crankshaft journal bearing play
-Excessive crankpin bearing play
SERVICE INFORMATION
WORKING PRACTICE
All bearing inserts are selective fit and are color coded .
Select replacement bearing from color code table.
SERVICE DATA
Item
Standard
Service Limit
Crankshaft
Journal 0 .D.
35.985-36.000 mm (1.4167-1.4173 in.)
Crank pin O.D.
35.985-36.000 mm (1.4167-1.4173 in.)
0-0.03
(0-0.0012 in.)
0.15-0.30 mm (0.0059-0.0118 in.)
0.05mm
0.40mm
22.85-22.90 mm
0.020-0.046 mm
22.75mm (0.8957 in.)
0.08mm (0.0031 in.)
Runout
Connecting rod side clearance
Crankcase
Upper case crankshaft holder width
Crankshaft oil clearance
10-2
(0.8996-0.9016 in.)
(0.0008-0.0018 in.)
35.940 mm (1.4150 in.)
35.940 mm (1 .4150 in.)
(0.0020 in.)
(0.0157 in.)
~HONDA
~
CB750
CRANKSHAFT/CONNECTING RO"O
CRANKSHAFT
REMOVAL
If necessary, remove the cylinder head,
cylinder and pistons.
Separate the crankcase.
NOTE
When the pistons are not removed,
remove the connecting rod big end
bearing caps.
Remove the mainshaft from the primary
drive chains.
Take out the crankshaft together with the
primary drive chains.
UPPER CRANKCASE INSPECTION
Measure the. journal holder width of the
upper crankcase.
SERVICE LIMIT: 22.75 mm (0.8957 in.)
CONNECTING ROD SIDE
CLEARANCE
Inspect the connecting rod side clearance
on the crankpin.
SERVICE LIMIT: 0.40 mm (0.0158 In.)
10-3
Q.\ HONDA
CRANKSHAFT/CONNECTING ROD
CONNECTING ROD
REMOVAL
Loosen connecting rod cap nuts.
Remove the connecting rod bearings, and
check for wear or damage.
CRANKSHAFT INSPECTION
Measure the crankshaft for runout.
SERVICE LIMIT : 0.05 mm (0.0020 In.)
CRANKPIN OIL
CLEARANCE
INSPECTION
Assemble the connecting rod inserts in
each rod cap. Place a plastigauge strip
across each crankpin.
NOTE
Clean all oil from the bearing inserts
and crankpins.
Install each connecting rod on the
corresponding crankpin and torque to
specifications.
TORQUE: 1.8-2.2 kg-m (13.0-15.9ft-lbs)
10-4
~
CB750
W'\HO NDA
~ CB750
CRANKSHA FT/CONNE CTING ROD
Remove the caps and measure the
plastigauge with the scale on the gauge
bag.
SERVICE LIMIT: 0.08mm (0.0032 in.)
CRANKSHAF T JOURNAL OIL
CLEARANCE
Put the lower bearing inserts in place and
install the crankshaft. Put a piece of
plastigauge across each journal, avoiding
oil holes.
NOTE
Wipe clean oil from the bearings and
journals.
Install the lower crankcase. Install the
mounting bolts and torque them evenly.
TORQUE: 2.0-2.5 kg-m (14.5-18.1 ft-lbs)
Remove the caps and measure the
compressed plastigauge on each journal.
SERVICE LIMIT: 0.08 mm (0.0032 In.)
If the clearance exceeds the limit, the
bearings should be replaced.
10-5
CRANKSHAFT/CONNECTING ROD
~HONDA.
~ CB750
CRANKPIN BEARING SELECTION
Determine and record each crankpin O.D.
code number stamped on the crankweight
on the drive sprocket side (or measure the
crankpin O.D.)
Record the corresponding connecting rod I.D.
code number (or measure it).
Cross reference the crank and bearing
codes in the chart to determine the replacement bearing color.
®
!
/y,::::::r.t--L: 3 3 4 3
!
Crankpin
Connecting
rod big
4
5
36.00035.995
35.99535.990
35.99035.985
B (Brown)
B (Brown)
A (Black)
C (Green)
B (Brown)
0 (Yellow)
C (Green)
0.0
end 1.0.
39.024
3
-39.016
,----------,
39.016
- 39.008
1 _________
C (Green),
L
39.008
- 39.000
0 (Yellow)
Inspect the crankpin oil clearance.
STANDARD: 0.020-0.046 mm
(0.0008-0.0018 In.)
10-6
......___
(2) GENERATOR SIDE
(3)COLOR CODES
~HONDA
~ CB750
CRANKSHAFT/CONNECTING ROD
CRANKSHAFT JOURNAL BEARING
CLEARANCE
Determine and record the main journal O.D.
code letter stamped on the crankweight on
the drive sprocket side.
Determine and record the corresponding
upper crankcase bearing support code
letter.
Q)
Cross reference the bearing support and
crank codes to determine the replacement
bearing color.
( I )UPPER CRANKCASE
L:IAABBB!
(Z)LOWER CRANKCASE
B
(1)CONTACK
BREAKER SID
1-----,
A
B
,-- -~--.
39.016
- 39.008
: A : 39.008
t_ ____ J - 39.000
l
B
:
L-----•
C
36.00035.995
35.995 35.990
35.99035.985
B (Brown)
B (Brown)
A (Black)
C (Green)
C (Green)
B (Brown)
D (Yellow)
Inspect the main bearing clearance.
STANDARD: 0.020-0.046 mm
(0.0008-0.0018 In.)
C (Green)
A
~
~0 .
fl
y
;;J)
.....
(2)GENERATOR SIDE
(3)COLOR
CODES
;4: APPLY THIN COATING OF
) MOLYBDENUM
~(
~
DISULFIDE GREASE
~
10-7
(;if\ HONDA
CRANKSHAFT/CONNE CTING ROD ~
CB750
CONNECTING ROD
ASSEMBLY
Prior to assembly, ensure that the connecting rods have the same weight code letter.
There are three weight code letters, D, F
and J.
Install the bearing inserts, and bearing
caps.
CAUTION
Be sure bearing caps are installed in
their correct location and the bearing
pawls point to the front of the
engine. Torque the cap bolts.
TORQUE: 1.8-2.2kg-m (13.0-18.1 ft-lbs)
CRANKSHAFT
ASSEMBLY
Check that the oil holes are not clogged .
Install the spark advancer shaft , 0 -ring and
oil seal.
Install the bearing inserts.
Install the gears and assemble the upper
and lower crankcases .
TORQUE : 2.0-2.5 kg-m (14.5-18.1ft-lbs)
10-8
a
" D,F,J"
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