TOKYO, Feb 20 (Reuters) - Japan's Nikkei share average fell for a second day after a disappointing private China factory survey hurt overall sentiment, dragging down companies with high exposure there such as Komatsu Ltd and Fanuc Corp. The Nikkei dropped 2.2 percent to 14,449.18, the biggest daily percentage decline since Feb. 4. The Topix declined 2.0 percent to 1,194.56, with all of its 33 subsectors in negative territory. The JPX-Nikkei Index 400, an index launched this year comprising firms with high returns on equity and strong corporate governance, dropped 2.0 percent to 10,808.73. Among the day's losers were Komatsu Ltd, off 3.2 percent, Hitachi Construction Machinery Co at 3.0 percent and Fanuc Corp, down 2.6 percent. The preliminary China Purchasing Managers' Index (PMI) from HSBC/Markit for February fell to a seven-month low of 48.3 in February from January's final reading of 49.5.