james, the part u r refering to is called a fuel mixture screw, it regulates how much fuel to that carb on idle,
it is essential to the running of the bike, i suggest a salvage yard with honda 750 of your year and just pocket it,, the screw closed will give no fuel, the more you open it the more fuel u get, I have a mine set at 3 turns out, runs great, good luck, mykey440