Check the parallelism error measured at 100 mm/3.93 in. from the longitudinal axis of the connecting rod: it must be H-h lower than 0.02 mm/0.00078 in. If not, change the connecting rod. The connecting rod is supplied in two types for coupling with the crankshaft A and В punched on the head.
Note. Use crankshafts and connecting rods of the same type.
| type | diameter of the connecting rod small end hole in mm (in.) |
| A | 45.019-45.025 (1.7723-1.7726) |
| В | 45.013-45.019 (1.7721-1.7724) |
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Gudgeon pin-connecting rod small end bush coupling
Coupling clearance: 0.015-0.032 mm/ 0.00059-0.00125 in.
Maximum wear limit: 0.05 mm/0.00196 in.
Note. When checking the clearance between the gudgeon pin and the connecting rod small end bush, note that, if the clearance is correct, the gudgeon pin lubricated with engine oil, in a vertical position, must drop out slowly due to the effect of its own weight (see diagram).
Changing the connecting rod small end bush
Using the tool shown in the diagram, extract the worn bush and, at the same time, insert the new bush (A).
Position the new bush on the end of the connecting rod, with the cut at 90° to the upper hole on the end of the connecting rod.
On the new bush, drill the lubrication holes to match the existing ones on the connecting rod small end.
Then bore the bush to obtain an internal diameter (D) of 19.015-19.028 mm/ 0.7486-0.7491 in.
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Connecting rod small end halt bearings
Note. Change the half bearings every time the engine is overhauled.
Spare half bearings are supplied ready for fitting. They must not be re-touched with scrapers or emery cloth.
There are two classes of half bearing, each identified by a colour (red and blue). They consist of an outer steel support and an internal galvanised lead coating.
- New red half bearing thickness: 1.482-1.487 mm
- New blue half bearing thickness: 1.486-1.491 mm
The table indicates the half bearings to be fitted based on the type of crankshaft and connecting rod.
| shaft class | connecting rod class | half bearing color |
| A | A | RED+BLUE |
| A | В | RED+RED |
| В | A | BLUE+BLUE |
| В | В | RED+BLUE |