All you should need is new float bowl seals, like #20-8035 here:
https://www.partsnmore.com/parts/honda/cb750k/?filters[category]=carburetor&filters[fitting]=custom
and possibly new float valves, #48-5009 (same place).
If the fuel tees leak (very rare) you will need 8 O-rings in size 1.9x7.9 or 2x8mm. If you can't find those, PM me for a set, they are cheap.
When you remove the brass parts, soak them in carb cleaner or lacquer thinner overnight, then poke all the holes clear. The pilot jets are small, and if you can't see thru their tiny hole it might be blocked. If so, get a piece of stranded wire (I use one strand from a #16 AWG wire) and poke thru from the top side to the bottom side, as that is the direction away from the crud. The hole is tapered and tiny, so go a little at a time until you can poke thru. Clean them all up, reinstall. The float level is 26mm in those carbs, measured from the notch on the sides of the body to the tops of the floats without pressing down on the float valves.
