Norton Engine Data

The table below shows data for Norton singles from 1928 to 1955.

A couple of notes:

• Valve and ignition timing given in inches for all models except the 30 and 40, these are given in degrees.

• Notation for valve timing as follows:

  • IO - Inlet Opening (Before TDC)

  • EC - Exhaust Closing (After TDC)

• When tappet clearances are given as ‘zero’ pushrods should be free to rotate with no perceptible up and down movement.

• Tappet clearances are running clearances and taken when cold. Clearances for setting valve timing may vary from these figures. Consult your manual to confirm.

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