The West German Olympic Committee voted today, 59 to 40, not to send a team to the Moscow Olympics this summer.

The decision was a big boost for the U.S.-led boycott. The West German action now stands against recent decisions by sports chiefs in France and Britain to go to Moscow and is expected by U.S. officials to tilt opinions in Western European countries that are still undecided.

While today's vote was welcomed by the Bonn government and opposition parties, there was little joy when the final tally was announced. No one in the meeting room cheered as the announcement came, following four hours of speeches for and against.

The Olympics issue posed a sharp dilemma for this country, whose security is bound to the United States but which also has close links to Soviet-led Eastern Europe.

Soviet officials have been threatening that West German relations with East Germany would suffer if Bonn did not send a team to the Moscow Olympics.

But the Bonn government, seeing the matter as a test of ties to the United States, last month strongly recommended that the nation's athletes boycott the Games. It was expected that a majority of West German sports chiefs would support the government's position.

The decision was all the more painful for the national committee, since West German athletes again had been expected to win more Olympic medals this summer than any other West European nation.

West German sports leaders were split on the question. The national committee's president, Willi Daume, a member of the International Olympic Committee and chief spokesman for sending a team, urged his colleagues, to "think of our sportsmen."

The leading advocate of a boycott, German Sports Federation chief Willi Weyer, told the assembly that the source of the conflict over the Games was not the U.S. appeal to its allies to stay away but "the march of the Red Army into Afghanistan."

Weyer scorned the idea that sports have nothing to do with politics and derided the IOC for not standing up to Moscow.

"The IOC was always strong against weak countries and it was always weak against strong countries," he said.

The West German decision has been considered crucial by U.S. officials to sway votes still to be taken in other countries during the nine days left before the deadline for accepting Olympic invitations.

The only other West European committees committed to a boycott are Liechtenstein, Monaco and Norway. Countries still to decide include the Netherlands, Spain, Belgium, Luxembourg, Sweden, Ireland, italy, Austria, Australia and Japan.

[The Portuguese Olympic committee decided tonight to ignore a government call for a boycott of the Games and said its athlets would compete in Moscow, Reuter quoted informed sources in Lisbon as saying.]

Among the key countries whose Olympic committees have voted to stay away from Moscow are Canada, Kenya, China and Argentina. At least 42 committees have voted to join the boycott.

Some West German Olympic officials voiced concern today that with France and Britian now seemingly committed to sending teams to Moscow, the German athletes could end up virtually alone in Western Europe in supporting a boycott.

Athletes who witnessed the West German vote expressed bitter disappointment at watching their Olympic dreams dissolve.

"Sports has bowed to politics. Politics now bears responsibility for the consequences," said fencing Olympic gold medalist Thomas Bach, who spoke for the athletes at the meeting.