They survived monsoon rains in India, sand storms on the Sahara Desert and blizzards in the mountains of New Mexico. They slept under bridges in the Sudan beside dead goats, had guns pointed at them by two armies and contracted diseases.

During their 13,500-mile bicycle trip through 16 countries, a trip that began last December and ended this week in front of the Capitol building, three young bikers for Project Hope saw a world that travel posters never show.

"The chaos of the world really made an impression. The poverty stunned me," said Dave Duncan of Kansas, the 24-year-old leader of the two-wheeled trek for charity that included his 23-year-old brother Don and Jim Logan of Oklahoma. An Alexandria, Va. cyclist, David French, quit after four months when he became ill with bacterial bronchitis.

If the world seemed strange in places to Logan and the Duncans, the three midwesterners did not exactly blend into the background of the places they visited. The sight of these fair-haired men, riding 18-speed bicycles loaded with about 100 pounds of gear each, was enough to disrupt entire villages.

"There's nothing like riding into an Asian bazaar, dodging camels," said the elder Duncan, a journalist and folk guitarist who bears a blue-eyed resemblance to Luke Skywalker. "We looked like a combination of Lawrence of Arabia and Star Wars Imperial Troopers."

The trip, which was Duncan's idea, concocted while talking to his track coach at Vassar College, began ominously. A few nights after flying to Madrid to begin the 3,000-mile European portion of the ride, the bikers were roused at gunpoint from their tents by Spanish soldiers. Some hasty, broken-field linguistics convinced the soldiers that they were no threat to the country.

A few weeks later, while camped beside a minefield on the Gaza Strip, the bikers were surrounded by Israeli soldiers who thought they might be Palestinian spies.

"The scary thing was there had been explosions all night," said Don Duncan, who made a photographic record of the trip for National Geographic. "Suddenly lights were flashing, people were screaming and guns were pointed at us." Explanations again were called for.

The bikers were surprised by the response they got in remote parts of the world when Project Hope was mentioned. The shirts they wore advertising their connection with the non-profit, international health organization were ideal calling cards. Many people wanted to talk about the hospital ship Hope, which sailed the world for 14 years bringing modern medicine to countries that needed it. The ship was retired in 1974.

In Asian villages, they were entertained by local chiefs who served them tea and coffee. In the Mideast, crowds swarmed around them, wanting to look and touch these Americans on wheels.

"You almost feel like the Beatles on tour," said Dave Duncan. "You have to smile and wave, wave and smile. It got to be a little overwhelming."

But even in the friendliest places, there was an inherent hostility from the weather and sanitation standards that their bodies could not easily adjust to.

"You'd spend the better part of each day looking for food you could eat, water to drink and a place to sleep," said Dave Duncan.

"We all got dysentery," added the 33-year-old Logan, who worked in Washington as an aide to an Oklahoma congressman for eight years before setting out on the trip. "We had to live the life we saw. We didn't see it from a bus or a train."

Even relatively insignificant hardships, like equipment failure, could make a day miserable. Logan remembers one 140-degree afternoon in Nepal when he had a dozen flat tires in a row. "I wanted to just sit down and cry."

During the 380-day trip, the bikers endured monsoons, typhoons, snow and stand storms. They crossed six mountain ranges and parts of four deserts. Dave broke his hand. Jim broke a toe. And Don, the hardluck kid if there ever was one, contracted salmonella in Bangkok and had to return home for treatment. The day he was let out of the hospital, he broke his shoulder in a swimming accident. Last week in South Carolina, his bike rolled into a rain drain and he broke his right elbow.

But all three are reluctant to mention their problems. They seem so trifling compared to the conditions they encountered along the way.

"I wrote a story for a Kansas City newspaper about the most miserable day of my life--June 1, 1982 in Utter Pradesh in northern India," said Dave Duncan. "It's a state smaller than California with three percent of the world's population. It was incredibly hot and humid. We all got very sick. There were deformed people everywhere. The tragic thing was, that was one day out of my life and an average day for them."

On Thursday the Hope bikers were lauded on the steps of the Capitol by half a dozen congressmen after the last leg of their trip from the Lincoln Memorial, accompanied by about 30 bikers from a local cycling club. Mayor Marion Barry proclaimed it Project Hope Day. Logan confessed a need for escape.

"I'm a person who demands solitude and I haven't had it for 380 days," said Logan. "I'm looking forward to becoming an absolute hermit for a while."