JAPAN SETS ASIDE YEN FUNDS TO PREVENT DLR FALL The 50-day provisional 1987/88 budget, adopted today by the government, allows the Finance Ministry to issue up to 14,600 billion yen worth of foreign exchange fund financing bills, government sources said. Foreign exchange dealers said the yen funds would be used to buy dollars, to prevent a further dollar fall. The government sources said the amount, covering the first 50 days of the year starting April 1, accounts for more than 90 pct of the 16,000 billion yen in bills incorporated in the full budget.