The Bombay Stock Exchange benchmark Sensex today opened 86 points lower on weak Asian cues.The 30-share index, which gained over 922 points in the previous four sessions, shed 86.75 points, or 0.51 per cent to 16,857.88 points in the first five minutes of trading.Metals, realty, technology, IT and banking sectors stocks were trading in the negative with losses extending up to 1.13 per cent.The wide-based National Stock Exchange index Nifty fell by 31.30, or 0.61 per cent, to 5,055.00 points.