So that's what 47-year-old motorcycle engine oil looks like

I know for a fact that my MV 175 was last used in 1964, so that makes the black treacle that came out of its sump on Friday 47 years old. The amount of mud and sand-type substance in the oil filter suggests that this bike was possibly used for ploughing Tuscan fields rather than gracing genteel roads that the MV Agusta name might suggest. I think I'm going to have to check out the main bearings now - at least there was oil in it rather than none at all which can only be a good thing.