Hi Bob.
The timing side housing on my crankcase is 1.689 thou and I have had a bronze bush made 2 thou over to suit. Knowledgeable members on this forum suggest the bush O.D should be approx. 2 thou larger than the crankcase I.D for a neat fit. I do not know what the original standard size should be but I did remove , "what appeared to be an original", white metal bush from these crankcases.I have seen on Ebay in England someone who makes timing size bushes, so you could get one made to suit your crankcases and crankshaft as I have done. I have not fitted my bush as yet but when I get to that point I will put the bush in the freezer overnight and heat the crankcases in the B.B.Q
