Geboers Goes Out on Top in Grand Prix : Motocross: Retiring world champion wins first event at San Bernardino’s Glen Helen Park.

World motocross champion Roger DeCoster tried for years to win a United States motocross Grand Prix at Carlsbad when he was a rider, but he could never pull it off. Sunday, in his first USGP as a promoter, he came out a winner.

The Motul U.S. 500cc Grand Prix at Glen Helen Park had little at stake except the prestige of the sport, but its results pleased just about everyone.

Eric Geboers, the world champion from Belgium, went home the overall winner to close out a Grand Prix career that saw him win five world championships overall and 11 of 24 individual motos this season. He had announced his retirement when the clinched the 1990 crown.

Rick Johnson, from El Cajon, won the second 40-minute moto to prove to all that he has recovered from a severe wrist injury that had curtailed his career since March 1989.

DeCoster was all smiles as he surveyed the crowd that swarmed over the brown hills of Glen Helen. It was reminiscent of the golden days of motocross at Carlsbad Raceway a decade ago.

“I am very happy,” said DeCoster, who was the man most instrumental in popularizing the sport in the United States in the early 1970s when he was the No. 1 rider in the world. “I was pleased to see all the people, but I was more pleased that they saw some great racing.”

DeCoster estimated the crowd at 15,000, but many observers felt it was a cautiously low figure.

“It was the best USGP I have ever seen,” Geboers said. “I say, ‘Well done, Roger.’ ”

Geboers’ first moto victory, a 40-minute fender-to-fender duel between his Honda and Johnny O’Mara’s Kawasaki was one of the most competitive in USGP history. O’Mara got off the line first, closely followed by Geboers, but it only took three loops of the 1.3-mile course before Geboers slipped past O’Mara on a tight corner at the bottom of the Yamaha Dropoff, a 65-foot jump on the east end of the course.

From then to the finish of the 21-lap race, O’Mara would close to a bike length of Geboers over the lower half of the course, which was laid out like stadium Supercross. But once the riders left the start-finish line and started up the sweeping high-speed portion that was more European-like in its style, Geboers would pull slightly ahead.

The pace never slackened as Geboers and O’Mara seemed to go faster and faster with each lap. It ended with O’Mara tucked in behind Geboers’ tailpipe.

“I gave it the best I had,” Geboers said. “I was riding over my limit. I was so exhausted that I became sick between the motos. It was the hardest moto I rode all year.”

Far back, Johnson finished third, Jeff Matiasevich fourth and England’s Kurt Nicoll fifth.

If anyone left unhappy, it had to be the Kawasaki contingent. After O’Mara lost a heartbreaker in the first heat, Matiasevich, from La Habra Heights, saw his moment of glory disappear in the second.

Matiasevich, riding in his first 500cc race, took the lead from Australia’s Jeff Leisk before the first lap was completed and built up a substantial margin over the first half of the 40-minute moto.

Geboers, knowing he had to finish at least third to win overall if Matiasevich held on, was fourth, just ahead of Johnson. Nicoll and Leisk were second and third. When Nicoll fell and was bumped by Geboers, Johnson used the confusion to pass all three riders and move into second behind Matiasevich.

It took Johnson, riding with a brace on his tender wrist, four laps to catch Matiasevich, and once he tasted the lead there was no challenging Johnson. The only question then was if Matiasevich could hold off Geboers.

Geboers, fighting off nausea and exhaustion, would not be denied. With three minutes remaining, he caught Matiasevich where the course dipped into a canyon gully.