NATURE OF RELEASE: Modification to exhaust valve guides.
DISTRIBUTION: Worldwide (Distributors and Dealers).
EXPLANATION: The design of exhaust valve guide NMT2011 has been revised to prevent excessive oil passage between the valves and guides. The upper end of the guide has been shortened so that the taper on the valve stem cannot enter the neck of the guide which would cause a pumping action. To avoid reducing the supporting length of the guide, the lower end of the guide has been lengthened by a similar amount. The modified valve guide is being supplied against part number 063527, and as stocks are exhausted, the later guide will supersede the earlier type directly
ACTION: Until dealer stocks of the taller guide are exhausted, ensure where possible that exhaust valve guides are used in pairs.

May 1972

Norton Villiers Canada Limited