A full teardown and rebuild of the carbs is in order. The link below should help. Don't purchase "carb kits" other than maybe an O-ring kit from cycleorings.com. You need to fully ungang the carbs, soak each body in carb dip for several hours, followed by rinsing and blowing out the passages with compressed air. Z1 Enterprises is a good place for gaskets for the float bowl and top as needed.
members.dslextreme.com/users/bikecliff/i.../vm_carb_rebuild.pdf
Second, do a conventional tune up including points check/gap/possible replacement, new plugs, and I'd do new plug wires and caps while you are there.
Needless to say a new battery and tires/tubes will be needed. New fresh OEM cables are a thing of beauty as well.
Clean out the gas tank of old gas and derust as necessary.
Pop out the caliper pistons, clean out, and inspect things like the pistons for pitting. New OEM caliper seals and pistons as needed. New brakes lines upon reassembly.
There are other tasks but that will keep you going for a while. Personally, I don't even bother trying to start an old bike like that until all the maintenance tasks are up to date. It's a futile effort since the maintenance needs to be done anyway.