Norton Commando Workshop Manual

## Engine/Primary Transmission

# C

### SECTION C18

### REMOVING CONNECTING RODS

Remove the connecting rods by releasing the two self locking nuts when it should be possible to pull the connecting rod away from the cap by hand pressure. The bearing shells remain in position at this stage but if they are to be re-used, they must be protected from dirt and possible damage. It is vitally important that at no stage are the connecting rod end caps interchanged between rods and it is equally important that the end caps should not be reversed on their own connecting rods.
A scribe marking is used on the connecting rod and end cap to show the correct direction of fitting. The locating tabs on both of the bearing shells fit to the same side of each connecting rod.

### SECTION C19

### DISMANTLING THE CRANKSHAFT

It is to be expected that the crankshaft assembly which is now to be stripped will contain approximately one teacup full of oil and provision should be made for collecting this oil in a suitable receptacle. Before parting the crank cheeks from the flywheel it is recommended that the flywheel be marked e.g. "T.S." for timing side so that it is not reversed during reassembly. Proceed as follows:
1 | Slacken the fixed nuts on the timing side securing the crank cheek to the flywheel, noting that the nuts have been centre punched during assembly and may be expected to be extremely tight.

2 | Jar the crank cheeks free from the flywheel using a hammer and soft drift. The drive side crankshaft will come away complete with the two studs, tab washer and nuts which can now be removed if desired.
Dependent upon mileage there is likely to be a considerable build up of sludge and foreign matter in both the crank cheeks and the recess in the flywheel. This foreign matter must be cleaned out most thoroughly.
Tool No. 063970 is available to remove roller bearing races from the crankshaft.

### SECTION C20

### CRANKSHAFT INSPECTION AND REGRINDING

Wash each crank cheek in clean petrol and blow dry with an air line. Examine the big end journals for scoring and remove light score marks by the use of smooth emery tape. If there is excessive scoring or ovality and it exceeds 0.0015 in. ( .0381 mm) on the big end journals regrinding is necessary.
The regrind sizes are shown in Fig. C28. The revised big end journal sizes necessitate the use of connecting rod shell bearings of the correct undersize. The steel backed big end shells are finished to provide the correct diametrical clearance and must not, under any circumstances, be scraped. Shell bearings are available in undersizes of minus 0.010 in., minus 0.020 in., minus 0.030 in. and minus 0.040 in.

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