THE CIRCUS goes on the day after a performer falls off the high-wire.

Traditionally, a roller-coaster does better business after someone gets killed or injured on the ride, because people love to prove they are tougher than death.

Some see it as bravery. Others call it crazy.

And some just don’t think about it, because to do so is to ensure one’s own doom.

And so it is that boxing will go on again this weekend, six days after the death of Beethavean Scottland on the deck of the USS Intrepid, in the one section of New York that has always been home to roller coasters and circuses and freak shows, and sometimes, death.

The show must go on, and what better place for a show as garish and tawdry and dramatic and dangerous and exciting as professional boxing to go on than Coney Island?

And what more appropriate performer to headline the show than Hector Camacho Jr., whose father often seemed more suited to a sideshow than to a prize ring?

Camacho, an undefeated junior welterweight, will take a step up in class against Jesse James Leija, a former world junior lightweight champion and two-time conqueror of featherweight legend Azumah Nelson in the 10-round main event at KeySpan Park.

In a semifinal match, heavyweights Kirk Johnson and Larry Donald will fight 10 or less to determine which will remain in line for a title shot, and which should begin looking for work as a bouncer.

Most likely, the setting will be the star, as it is on the nights the Class A Brooklyn Cyclones call KeySpan home.

With the aging parachute jump looming behind the outfield fence, antique amusements the Cyclone and Wonder Wheel visible off to the left, and the Atlantic Ocean serving as a crashing backdrop to it all, tomorrow night’s fight show is guaranteed spectacle even if the fights turn out to be duds.

But if any act could stand up against the natural and man-made wonders all around, it is the Camachos, Sr. and Jr.

We’ve all seen the act of Camacho Sr., the original Macho Man, and yesterday, at a news conference held in the bumper-car pavilion of Astroland Park, we got to see it in all its hyperactive glory once again.

While promoter Dan Goossen tried to run a semi-respectable show, there was Camacho Sr., who is training his son, strutting around, mugging, wisecracking, and shadow-boxing. There wasn’t enough mustard at Nathan’s to cover the old guy, who easily retained his title, middleweight champion of the ADD.

By comparison, Camacho Jr., who made his dad a grandfather two years ago with the birth of his daughter Shaniah, seemed as subdued as a carnival barker on a rainy day.

“I’m different from my father,” 22-year-old Junior acknowledged. “I do some of the same stuff, but it’s just for marketing. Look at him, the way he carries himself, all that energy. That’s just the way he is. Me, I’m the way I am.”

So far, Camacho Junior has been very much like Camacho Senior in the ring. Fast, graceful, instinctive, lefthanded and cautious.

“The only thing I have that he doesn’t have,” said Junior, “is power. I have much more power than he does.”

“That’s what he thinks,” said Senior. “He’s starting to believe that stuff because he knocked a few people out. There ain’t nothing he can do, or will do, that I didn’t do. Good and bad.”

In fact, the unbeaten Camacho Junior has 18 KOs in 32 fights, the most recent a two-round knockout of someone named Larry LaCoursiere in April.

But he has yet to fight anyone as seasoned or as resilient as Leija.

“He better be a special fighter,” Leija said. “Or he’s making a big mistake.”

Yesterday, Junior Camacho tried to engage Leija in a game of Coney Island Chicken by climbing into the second car of the Cyclone, the 73-year-old pile of wood and steel at the corner of Surf Ave. and W. 10th St., and trying to coax Leija into the seat in front.

“C’mon, man, you’re first in the ring, you gotta be first on the ride,” he taunted. “Come on, be a man.”

Leija, from San Antonio, refused to ride the fearsome looking coaster.

“We got bigger roller coasters in Texas,” he said. “I’ll ride it after the fight.”

He agreed to have a photo taken while sitting in the front car, but then stalked off, looking angry.

“I ain’t gonna ride it either, then,” Camacho said. He, too, left with his handlers.

The coaster wound up making its run with just a reporter and a couple of promoters on board, which is how it is supposed to be.

Fighters need to be brave. Not crazy.