Norton Commando Workshop Manual

## Engine/Primary Drive

# C

### SECTION C5

### VALVE GUIDE RENEWAL

The cast iron valve guides are a tight interference fit in the cylinder head and can be removed and refitted only after heating the cylinder head to a temperature of 150° to 200°C. A special Service Tool 063964 is available for removing and refitting the valve guides.
Proceed as follows:
1 | Place the tool adaptor marked "Remover" hollow end down over the valve guide.
2 | Place the cranked and threaded stem through the valve guide from the hemisphere.
3 | Hold the cranked stem to prevent it turning and scrow on the handie (see Fig. C6). As the handie is tightened the guide and cranked stem will be pulled through into the remover body.

New valve guides are available in oversizes of +0.002 in., +0.005 in., +0.010 in. and +0.015 in. The valve guide to cylinder head interference shouid be .0015 in. -.0025 in. and if there is ovality and oversize guides are to be fitted the valve guide bores in the head must be reamed tosuit.Asamatterof course usethe improved inlet guides with valve guide-to-stem seals during reassembly.
Fit new valve guides as follows:
4 | Place the new guide in line with the bore in the cylinder and place the adaptor marked "Replacer" from Service Tool 063964 over the guide.
5 | Place the replacer stem through the cylinder head and bore of the valve guide and locate the abutment to the valve seat.
6 | Fit the handie and turn to pull the guide fully home into the head. If necessary the abutment can be prevented from turning by the use of a suitable key in the socket provided.
7 | Recut the valve seats at the points where new guides have been fitted. This operation is des cribed in Section C6.

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