Norton Service Release Database N2/09

SERVICE RELEASE N2/09

NATURE OF RELEASE: Crankshaft main (roller) bearings MODELS AFFECTED: 1972 Commando (all models) DISTRIBUTION: Worldwide (Distributors and Dealers) EXPLANATION: In order to extend main bearing life, a change of roller main bearing specification has now been authorized, and fitted on production engines from engine number 211891. The new roller bearing is designated "Superblend" with an increased load carrying capacity and are supplied under part number 063906 (manufacturers part number R & M 6/MRJA30.   ACTION: Where engine units are stripped for examination, or the need for main bearing replacement, fit only roller main bearings part number 063906 in place of the previously specified 063114. The new bearings are fully interchangeable, and should be fitted in pairs for maximum reliability. Note: The new bearings may also be fitted to advantage to 1971 and earlier Commando machines, provided care is taken fitting the inner spool to the right side crankshaft journal (was 1.1807in. 1.1812in.) diameter, now 1.1812in. 1.1815in. diameter. Also crankshaft fitted end float should be checked, and shimmed where necessary to provide 0.010in. min. 0.020in. max. end float using shim part number NMT2196A as necessary. August 1972 Norton Villiers Canada Limited