Inspection

CRANKSHAFT
Crankshaft Runout





Using a dial gauge, measure runout at center journal. Rotate crankshaft slowly. If runout exceeds its limit, replace crankshaft.
Limit On Runout: 0.06 mm (0.0023 inch)

Crankshaft Thrust Play





Measure this play with crankshaft set in cylinder block in the normal manner, that is, with thrust bearing and journal bearing caps installed. Tighten crankcase bolts to specified torque in such order as indicated in figure.
Tightening Torque:
(a): 60 Nm (6.0 kg-m, 43.5 ft. lbs.)
(b): 25 N m (2.5 kg-m, 18.0 ft. lbs.)








Use a dial gauge to read displacement in axial (thrust) direction of crankshaft. If its limit is exceeded, replace thrust bearing with new standard one or oversize one to obtain standard thrust play.
Crankshaft Thrust Play:
Standard: 0.10 - 0.35 mm (0.0039 - 0.0138 inch)
Limit: 0.42 mm (0.0165 inch)
Thickness Of Crankshaft Thrust Bearing:
Standard: 2.500 mm (0.984 inch)
Oversize 0.125 mm (0.0049 inch): 2.563 mm (0.1009 inch)

Out-of Round And Taper (Uneven Wear) Of Journals





An unevenly worn crankshaft journal shows up as a difference in diameter at a cross section or along its length (or both). This difference, if any, is determined by taking micrometer readings. If any one of journals is badly damaged or if amount of uneven wear in the sense explained above exceeds its limit, regrind or replace crankshaft.
Diameter of journal: 57.982 - 58.000 mm (2.2828 - 2.2834 inch)
Limit On Out-of-Round And Taper: 0.01 mm 10.0004 inch).
Out-of-Round: A - B
Taper: a - b

Main Bearings
General Information:





- Service main bearings are available in standard size and 0.25 mm (0.0098 inch) undersize, and standard size has 5 kinds of bearings differing in tolerance. To distinguish undersize bearing, it is painted red at the position as indicated in figure. Undersize bearing thickness is 2.124-2.128 mm (0.0836-0.0337 inch) at the center of bearing.





- Upper half of bearing has oil groove as shown in figure. Install this half with oil groove to cylinder block.
- Lower half of bearing does not have oil groove.

Inspect
Check bearings for pitting, scratches, wear or damage. If any malcondition is found, replace both upper and lower halves. Never replace either half without replacing the other half.

Main Bearing Clearance
Check clearance by using gaging plastic according to following procedure.
1. Remove lower crankcase.
2. Clean bearings and main journals.





3. Place a piece of gaging plastic the full width of bearing (parallel to crankshaft) on journal, avoiding oil hole.





4. Install lower crankcase to cylinder block. Tighten crankcase bolts, following sequence in figure. Tighten crankcase bolts to specified torque.
Tightening Torque:
(a): 60 Nm (6.0 kg-m, 43.5 ft. lbs.)
(b): 25 Nm (2.5 kg-m, 18.0 ft. lbs.)

NOTE: Do not rotate crankshaft while gauging plastic is installed.





5. Remove lower crankcase and using scale on gaging plastic envelop, measure gaging plastic width at its widest point. If clearance exceeds its limit, replace bearing. Always replace both upper and lower inserts as a unit. A new standard bearing may produce proper clearance. If not, it will be necessary to regrind crankshaft journal for use of 0.25 mm undersize bearing. After selecting new bearing, recheck clearance.
Bearing Clearance:
Standard: 0.026 - 0.046 mm (0.0010 - 0.0018 inch)
Limit: 0.060 mm (0.0023 inch)

Selection Of Main Bearings
Standard Bearing: If bearing is in malcondition, or bearing clearance is out of specification, select a new standard bearing according to following procedure and install it.





1. First check journal diameter. As shown in figure, crank web No.2 has stamped numbers. Three kinds of numbers ("1", "2" and "3") represent following journal diameters.
Stamped Numbers: 1
Journal Diameter: 57.994 - 58.000 mm (2.2832 - 2.2834 inch)
Stamped Numbers: 2
Journal Diameter: 57.988 - 57.994 mm (2.2830 - 2.2832 inch)
Stamped Numbers: 3
Journal Diameter: 57.982 - 57.988 mm (2.2828 - 2.2829 inch)
Stamped numbers on crank web No.2 represent journal diameters marked with an arrow in figure respectively. For example, stamped number "1" indicates that corresponding journal diameter is 57.994- 58.000 mm.





2. Next, check crankcase (bearing cap) bore diameter without bearing. On lower crankcase five alphabets are stamped as shown in figure. Three kinds of alphabets ("A","B" and"C") represent following cap bore diameters.
Stamped Alphabet: A
Bearing Cap Bore Diameter (Without Bearing): 62.000 - 62.006 mm (2.4409 - 2.4411 inch)
Stamped Alphabet: B
Bearing Cap Bore Diameter (Without Bearing): 62.006 - 62.012 mm (2.4412 - 2.4414 inch)
Stamped Alphabet: C
Bearing Cap Bore Diameter (Without Bearing): 62.012 - 62.018 mm (2.4414 - 2.4416 inch)
Stamped alphabets on lower crankcase represent crankcase bore diameter marked with an arrow in figure respectively. For example, stamped alphabet "A" indicates that corresponding bearing cap bore diameter is 62.000 - 62.006 mm.





3. There are five kinds of standard bearings differing in thickness. To distinguish them, they are painted in following colors at the position as indicated in figure. Each color indicated following thickness at the center of bearing.
Color Painted: Green
Bearing Thickness: 1.993- 1.997 mm (0.0785 - 0.0786 inch)
Color Painted: Black
Bearing Thickness: 1.996 - 2.000 mm (0.0786 - 0.0787 inch)
Color Painted: Colorless (no paint)
Bearing Thickness: 1.999 - 2.003 mm (0.0787 - 0.0788 inch)
Color Painted: Yellow
Bearing Thickness: 2.002 - 2.006 mm (0.0788 - 0.0789 inch)
Color Painted: Blue
Bearing Thickness: 2.005 - 2.009 mm (0.0789 - 0.0790 inch)
4. From number stamped on crank web No.2 and alphabets stamped on lower crankcase, determine new standard bearing to be installed to journal, by referring to table shown below. For example, if number stamped on crank web No.2 is "1 " and alphabet stamped on lower crankcase is "B", install a new standard bearing painted in "Black" to its journal.
Alphabet Stamped On Lower Crankcase (Cap Bore Diameter): A
Number Stamped On Crank Web (Journal Diameter): 1 (Green)
Number Stamped On Crank Web (Journal Diameter): 2 (Black)
Number Stamped On Crank Web (Journal Diameter): 3 (Colorless)
Alphabet Stamped On Lower Crankcase (Cap Bore Diameter): B
Number Stamped On Crank Web (Journal Diameter): 1 (Black )
Number Stamped On Crank Web (Journal Diameter): 2 (Colorless)
Number Stamped On Crank Web (Journal Diameter): 3 (Yellow)
Alphabet Stamped On Lower Crankcase (Cap Bore Diameter): C
Number Stamped On Crank Web (Journal Diameter): 1 (Colorless)
Number Stamped On Crank Web (Journal Diameter): 2 (Yellow)
Number Stamped On Crank Web (Journal Diameter): 3 (Blue)
New standard bearing to be installed.





5. Using gaging plastic, check bearing clearance with newly selected standard bearing. If clearance still exceeds its limit, use next thicker bearing and recheck clearance. If clearance can not be still brought to within its limit even by using a new standard size bearing, regrind the crank pin to under size and use 0.25 mm undersize bearing.
Crankshaft Journal Diameter (0.25 mm undersize): 57.698 - 57.744 mm (2.2716 - 2.2733 inch).
6. When replacing crankshaft or cylinder block and lower crank case due to any reason, select new standard bearings to be installed by referring to number stamped on new crankshaft or alphabets stamped on new lower crankcase.

Crankshaft Position (CKP) Sensor Plate





- Check tech of plate for damage.
If any damage is found, replace crankshaft.

Oil Pump Sprocket





- Check teeth of sprocket for wear or damage.
If any damage or wear is found, replace crankshaft.

Oil Pump Chain





- Check oil pump chain for wear or damage.

Rear Oil Seal





Carefully inspect oil seal for wear or damage. If lip portion is worn or damaged, replace oil seal.

Flywheel





- If ring gear is damaged, cracked or worn, replace flywheel.
- If the surface contacting clutch disc is damaged, or excessively worn, replace flywheel.
- Check flywheel for face runout with a dial gauge. If runout exceeds its limit, replace flywheel.
Limit On Runout: 0.2 mm (0.0078 inch).

Cylinder Block
Distortion of gasketed surface.





- Using straightedge and thickness gauge, check gasketed surface for distortion and, if flatness exceeds its limit, correct it.
Flatness Limit: 0.06 mm (0.0024 inch).

Honing Or Rebating Cylinders





1. When any cylinder needs reboring, all other cylinders must also be rebored at the same time.
2. Select oversized piston according to amount of cylinder wear.
Size: Standard
Piston Diameter: 83.970 - 83.990 mm (3.3059 - 3.3066 inch).
Size: O/S 0.25
Piston Diameter: 84.220 - 84.240 mm (3.3157 - 3.3165 inch).
Size: O/S 0.50
Piston Diameter: 84.470 - 84.490 mm (3.3256 - 3.3263 inch).
3. Using micrometer, measure piston diameter.
4. Calculate cylinder bore diameter to be rebored as follows:
D=A+ B-C
D: Cylinder bore diameter to be rebored.
A: Piston diameter as measured.
B: Piston clearance = 0.02 - 0.04 mm (0.0008 - 0.0015 inch).
C: Allowance for honing = 0.02 mm (0.0008 inch).
5. Rebore and hone cylinder to calculated dimension.

NOTE: Before reboring, install lower tighten to specification to avoid distortion of bearing bores.

6. Measure piston clearance after honing.

Check Valve





Check check valve for clogging and ball for being stuck.