UPDATE 1-United says removing Boeing 787 from flight plans

Feb 21 (Reuters) - United Continental Holdings said on Thursday it was taking Boeing Co's grounded 787 Dreamliner out of its flying plans through June 5, except for the Denver to Tokyo Narita route scheduled for a tentative launch on May 12.

Meanwhile, Japanese investigators studying fuel leaks on the 787 found a problem with the paint on the equipment controlling the fuel-tank valve, the Nikkei news service reported, citing people familiar with the details.

The Dreamliner fleet has been grounded for the past five weeks due to problems with battery failure. Boeing is due to meet with the head of the U.S. Federal Aviation Administration on Friday to present measures designed to prevent such failures, a source told Reuters.

United spokeswoman Christen David said in a statement on Thursday that the carrier's Denver to Tokyo Narita International route, originally set to start March 31, had been postponed to May. The launch would ultimately depend on a successful resolution of the safety incidents that have grounded the 787.

"We remain committed to flying from Denver to Narita with the 787, and we will launch the route after the aircraft re-enters service," United's statement said.

Boeing was not immediately available for comment.

United, the only U.S. carrier currently operating the 787, has six of the planes.

Japan's Nikkei, citing sources, reported in its Feb. 22 morning edition that Transport Ministry investigators found deficiencies in how electrical-insulating paint was applied to a driving mechanism that opens and closes the 787's fuel-tank valve. The ministry also found foreign matter stuck on a switch on the mechanism.

The ministry is discussing the cause and measures to prevent recurrences with the U.S. Federal Aviation Administration and Boeing, the Nikkei report added.

In addition to the battery problem, investigators have been looking into a case in which a Japan Airlines 787 leaked fuel while taxiing to the runway for take-off at Boston's Logan International Airport in January.