Crankshaft Mechanism Measurement
SPECIAL TOOLS- Piston Ring Pliers tool No. 998 5424, or equivalent
- Drift tool No. 999 2413, or equivalent
- Drift tool No. 999 5309, or equivalent
- Magnetic Stand tool No. 999 9696, or equivalent
- Dial Gauge tool No. 999 9684, or equivalent
- Micrometer tool No. 999 9701, or equivalent
- Micrometer tool No. 999 9702, or equivalent
- Micrometer tool No. 999 9703, or equivalent
- Micrometer tool No. 999 9704, or equivalent
PROCEDURES
NOTE:
- For Crankshaft, Rods and Piston measurement see steps 1 through 12
- For Connecting rod Bushing replacement, see steps 13 through 16
CRANKSHAFT, RODS AND PISTONS, MEASUREMENT
1. Measure crankshaft
- Use micrometer tool No. 999 9703, or equivalent.
- Measure out-of-round and ovality of bearing journals.
- Measure at several points around circumference and along length.
2. Measure connecting rod journals
Diameter standard: 50.000 mm
Diameter undersize: 49.750 mm
Bearing seat width: 26.000 mm
Max. out-of-round: 0.004 mm
Max. ovality: 0.004 mm
Measure main bearing journals
Diameter standard: 65.000 mm
Diameter undersize: 49.750 mm
Axial bearing seat width: 26.000 mm
Max. out-of-round: 0.004 mm
Max. ovality: 0.004 mm
3. Check crankshaft straightness
- Use dial gauge tool No. 999 9684 and magnetic stand tool No. 999 9696, or equivalents.
- Support outermost main bearing journals in V-blocks.
- Turn crankshaft and measure radial throw of other main bearing journals.
Max. radial throw: 0.004 mm
4. Remove piston rings
- Use piston ring pliers tool No. 998 5424, or equivalent.
- Remove carbon deposits.
- Clean piston ring grooves by scraping with a scraping tool or fragment of ground piston ring.
- Check for, damage, wear, cracking.
5. Check piston ring side play, using new piston rings.
Piston ring side play:
Upper compression ring: 0.05-0.085 mm
Lower compression ring: 0.03-0.065 mm
Oil scraper ring: 0.02-0.055 mm
Piston ring dimensions, version 1 (1992-93)
Upper compression ring: 1.5 mm
Lower compression ring: 1.75 mm
Oil scraper ring: 3.0 mm
Piston ring dimensions, version 2 (1994-98)
Upper compression ring: 1.2 mm
Lower compression ring: 1.75 mm
Oil scraper ring: 3.0 mm
6. Measure piston diameter
Use micrometer tool No. 99 9704, or equivalent, and sliding calipers.
A = Overall piston height.
B = Height from wrist pin center to crown.
C = Measure piston diameter at right-angles to wrist pin hole at distance "C" from edge of skirt.
D = Piston diameter.
Dimensions A, B and C.
Dimension A: 59.9 mm
Dimension B: 35.9 mm
Dimension C: 16.0 mm
Standard piston diameters:
Piston marked C: 82.98-82.99 mm
Piston marked D: 82.99 33.00 mm
Piston marked E: 83.00 83.01 mm
Piston marked G: 83.017-83.032 mm
Oversize pistion diameter:
Oversize 1: 83.177-83.192 mm
Oversize 2: 83.377-83.392 mm
Max. difference in weight between pistons in same engine: 10 g.
7. Calculate piston clearance
Example
Measured cylinder diameter - 96.03 mm
minus
Measured piston diameter - 96.00 mm
equals
Piston clearance - 0.03 mm
96.03 - 96.00 = 0.03
Piston clearance should be: 0.01-0.03 mm (max)
8. Separate conrods and pistons
- First check that piston and conrod are marked.
- Pry circlip out carefully with a screwdriver.
- Push wrist pin out by hand.
- Clean and inspect conrods, bearing caps and bolts for damage, wear and cracking.
- Check length of conrod bearing cap bolts using sliding calipers.
Maximum length of conrod bearing cap bolt: 55 mm
9. Check wrist pin fit in pistons
- No play is allowed
- Wrist pin should slide gently but firmly through hole when pressed with thumb.
- If there is any play, replace piston.
10. Check wrist pin fit to conrods
- Wrist pin should slide through hole when pressed gently with thumb.
- If excessive play, measure wrist pin and fit new conrod bushing if necessary.
- Use micrometer tool No. 999 9701, or equivalent.
Wrist pin diameter: 22.996 mm - 23.0 mm
11. Check bearing seats at big end of Conrad
- Inspect bearing shells visually.
- If in doubt, measure out-of-round.
- Use dial gauge tool No. 999 9639.
Bearing seat diameter: 53.0 mm
Max. out-of-round: 0.006 mm
12. Check Conrad in alignment gauge
- Check straightness and twisting.
NOTE: Check that clamping surface of fork is round and free of burrs. Release and tighten expander at big end between each alignment check.
CONROD BUSHINGS, REPLACEMENT
13. Press bushing out
- Use drift tool No. 999 5309, or equivalent.
- Position drift correctly with short end downwards.
- Use drift tool No. 999 2413, or equivalent, as counterhold.
14. Press in new bushing
- Use drift tool No. 999 5309, or equivalent.
- Position drift correctly, long end downwards.
- Push drift right down.
NOTE: Make sure the hole in the bushing is aligned with the lubricating passage in the conrod.
15. Check wrist pin fit to new bushing.
- Wrist pin should slide through bushing under light thumb pressure, but without noticeable play.
- Machine bushing as necessary.
16. Check Conrad in a suitable alignment gauge
- Check for straightness and twisting.
NOTE:
- Check that clamping surface of fork is round and free of burrs.
- Release and tighten expander at big end between each alignment check.
17. Conrad, replacement
- Conrods are symmetrical and can be turned over if required.
Markings:
- Assemble conrod, check that bearing cap is correctly positioned.
- Tighten bolts to 20 Nm (15 ft. lbs)
- Put big end in clamp using copper spacers or similar tool.
- Mark both halves with the cylinder number using a center or number punch.