Take 2 or 3 same year bikes, take them completely apart, clean every single part, use the best parts on the 1st, 2nd best on 2nd, etc, zinc-plate all the hardware, refinish the aluminum, don't spend money on repainting (buy orig paint bodywork), get a parts manual, keep the bike original, new spokes make the difference, as do nice gauges, paint and seat, so blow some money on those items, motor rebuilding very expensive if you farm it out, do it in order and as quickly as possible (once they go on back-burner, they lose the required obsessive momentum.
That usually works.