but i'm worried that if i help you with the answer i'll become the CB500 fork expert and get burned by a selfish suspension jerk who reneges on a fork seal deal and i'll have to start a thread that gets all my cool friends and interweb lemmings all mushy with support.
1972 CB500 owners manual pg 73 ; 5.4 oz. (160 cc) ATF. Oil change not dry assembly.
1974 CB550 owners manual pg 76 ; 5.4~5.6 oz. (160~166 cc) ATF. Oil change not dry assembly.
1977 CB550F owners manual pg 74 ; 4.8~4.9 oz. (145~150 cc) ATF. Oil change not dry assembly.
Honda Shop Manual Pg 81 : 5.3~5.6 oz (155~165 cc) Honda ATF (at dissassembly) /CB500/
Honda Shop Manual Pg 135 : 5.4 oz (160 cc) /CB500/
Honda Shop Manual Pg 137 : 6.3~6.5 oz (185~191 cc) Presumably the Cb550 Supplement to the shop manual, added for 1974.
Honda Shop Manual Pg 157 : 5.6~5.8 oz (165~170 cc) Honda ATF, The Cb550F Supplement to the shop manual, added for 1975.
Shop manual doesn't list a fork oil capacity change for the K3 and F2 models. But, my owners manual does.
From my observations, there are three fork designs.
1) Cb500 71-73
2) Cb550 74-76 including F and K models
3) 77-78K and 77F models
I think the shop manual data on pg 137 is likely a misprint.