John B. Clyburn, a veteran D.C. contractor accused in an illegal scheme to win lucrative city contracts, testified yesterday that he never bribed city officials and that many of the government's allegations of wrongdoing are simply examples of business-as-usual in the world of D.C. contracting.

It was Clyburn's first chance to tell his version of events in the three-month-old federal trial, in which he and longtime friend David E. Rivers, former director of the city's Department of Human Services, are charged with conspiring to steer more than $2 million in contracts to companies owned by Clyburn or his friends.

Under questioning by his defense attorney, Thomas R. Dyson, Clyburn was asked whether he had ever given Rivers money in return for business.

"No, I have not," Clyburn replied from the witness stand in the courtroom of U.S. District Judge Joyce Hens Green.

"Has Mr. Rivers ever solicited money, real estate, stock or bonds in return for business?" Dyson asked.

"No, he has not," Clyburn asserted.

Dyson then steered his client through the allegations of illegal conspiracy surrounding several contracts, and Clyburn portrayed his actions as those of a typical businessman networking and soliciting contracts from the city.

Clyburn testified that he met Rivers in the early 1980s on a shuttle flight from New York, and approached him because Rivers then was working for the federal government with small and disadvantaged businesses. The two, he said, became friends, often talking on the telephone, attending social events and discussing business.

But where the government has charged favoritism and bribery in the award of contracts, Clyburn explained incidents in a different light.

For instance, there is the 1984 dinner meeting at which, the government alleged, Clyburn was given an opportunity to approve the city's prospective public health commissioner, Andrew McBride.

Clyburn testified that Rivers suggested the meeting, which also included former city administrator Elijah B. Rogers and Ivanhoe Donaldson, a close friend of the mayor's, to give McBride "three perspectives of D.C." and that it was clear McBride already had the job.

Clyburn said he reported to Rivers "on what I thought . . . . I said he was a very sincere person . . . and probably a good choice."

The government has alleged that as part of the conspiracy, Clyburn's firm hired a friend of McBride's, Charles Dickerson, as a consultant to influence the award of public health contracts to Clyburn's firm. Dickerson was paid by the city from part of the proceeds of a $36,000 contract that Clyburn's firm received from the public health commission.

Clyburn acknowledged hiring Dickerson, who then conducted a study of the health commission for McBride. But Clyburn said such a hiring procedure was "a normal practice" in the consulting world.

Prosecutors have alleged that as part of the conspiracy Rivers gave Clyburn's company a "sole source" contract -- one that did not require Clyburn to compete in a bidding process -- for a 1985 summer program to train students as drug counselors. The contract was worth more than $724,000, and prosecutors have alleged that the firm received a $288,000 advance it had not shown was necessary.

Clyburn testified yesterday that the District's contracting process was "inefficient," fraught with "cumbersome procedures" where "paperwork got lost in the shuffle" and contractors often had difficulty getting paid.

For small businesses such as his, Clyburn testified, late payments could be fatal, and he agreed to handle the summer program on short notice only if he received an advance.