Crank Regrinding:
Bernie Nicholson, Canadian authority on British motorcycle mechanics,
recommended having plain bearing type cranks reground by an automotive machine
shop when wear on conrod journals is .004" or greater, or ovality is .003" or
greater.
RH crankshaft main bushing journals, where applicable, should be reground when
worn .002" or more, to avoid losing oil pressure, and fitted clearance should be
.0015 to .002"
It is important that the machine shop be advised to retain original radius at
the ends of the bearing surface as if ground out to a sharp corner, crank
failure may result.