Norton Service Release Database N2/03

SERVICE RELEASE N2/03

NATURE OF RELEASE: Combat valve springs. MODELS AFFECTED: 1972 Combat engine DISTRIBUTION: Worldwide (Trade only) EXPLANATION: On certain Combat engines from the initial production batch, we have become aware of a condition which prevents the valves opening sufficiently   ACTION: At the first service or first convenient opportunity, check that the valve springs are not preventing the valves opening fully. With the fuel tank and rocker covers removed, turn the engine until any valve is opened fully, i. e. is depressed into the cylinder as far as permitted by the valve operating gear. At this stage push down the rocker adjuster against the valve stem, such as with an aluminium or wooden shaft, and ensure that the valve can move perceptibly as the spring is depressed further. Repeat this check on all valves in turn. Perceptible movement indicates that all is well but a lack of movement will necessitate the use of a new thinner bottom valve spring cup part number 063996 The thinner bottom cup is identified by the marking "IN" on the inner facing. As an alternative to using new cups, the NMT2073 may be reduced in thickness to 0.065in . (1.65mm). The above check applies only to engine number series 200004 to 202340.Thin bottom valve spring cup washers 063396 were fitted from 202341 to 202665. Heat insulating washers NM23392 and standard cup washers NMT2073 re-introduced from 202666. April 1972 Norton Villiers Canada Limited