Despite public pronouncements to the contrary, presidential envoy Clark Clifford failed to bridge the main differences between Turkey and the United States during his visit here, Western diplomatic sources said today.

Clifford spoke yesterday of an identity of views with Turkish leaders and said on his departure for Cyprus, where he arrived later today that his visit was "a useful start in reinvigorating" troubled Turkish-American relations.

But diplomats said the talks failed to settle differences over the American embargo on arms supplies to Turkey and Ankara's retaliatory closure of 26 U.S. bases on Turkish soil.

"The differences still exist," one Western diplomat said.

Turkey continues to insist that its defense arrangements with the United States and settlement of the Cyprus conflict are separate issues that should not be linked.

The United States still demands significant progress toward a Cyprus settlement before military aid and arms supplies are restored.

Turkish Premier Suleman Demirel told Clifford during the former Defense Secretary's two days of talks in Ankara, that he could not make concessions on Cyprus before general elections later this year.

He promised, however, to push for a Cyprus settlement if re-elected. In return, he asked the Carter administration to press for congressional approval of the military agreement.

Under the agreement, Turkey would reopen U.S. bases, including top-secret installations monitoring military movements in the neighboring Soviet Union.

U.S. officials said the bases are no longer a key bargaining point as most of their important functions had been replaced by bases elsewhere. "We cannot be blackmailed on this one," one official said.

Clifford said, "It is my belief that the two nations will be able to work out whatever details exist so that cooperation can continue."