I read your other thread, It appears as though you are fighting a power problem (bike will not go over 65mph). I think in the end you will find a actual problem. If your plugs are all firing and without missing or popping, although they may not be optimal, the bike should run faster than 65mph.
it is completely normal for the first few threads to be colored or sooty, the actual combustion sealing does not occur until the sealing washer.