From memory its 99cc in the primary and 180ish cc in each leg of the front forks. I've also come across something about oil levels (so many inches below the top or something like that) Sorry about the imprecision, but the correct numbers are in Roy Bacon's book, and I've lent my copy to a nearish neighbour who's rebuilding an early 50s plunger. The plunger capacities are much less than the swinging arm version, and Haynes is remiss in not saying so. I'm sure someone else on the forum will chime up with the exact quantaties shortly,
John
ps how about checking the workshop manual pages on this forum - they might hold the correct info.