Colby Raha, pro motocross rider, is attempting a death-defying jump … and he walked TMZ Sports through the insane stunt!

Raha, 31, will attempt to break his own world record for highest vertical jump off a quarter-pipe, which is currently 90 feet, gunning to fly 100 feet above one of the most iconic locales on the Las Vegas Strip Sunday afternoon, all to celebrate the grand opening of OMNIA Dayclub & Skybar.

“We’re here at the beautiful Caesars Palace fountains, where Evel Knievel and a bunch of other legends jump their bikes, and I’m going to be jumping my motorcycle, going for a world record,” Raha told Babcock.

He explains, “I’m going for the highest ever motorcycle jump in the air of all time. I’m going for 100 feet off the floor. It’s kind of like a half pipe. If you know Tony Hawk or a skateboarder, I’m doing it on a dirt bike. So I’m going straight up and down.”

If the level risk isn’t crystal clear … consider Knievel attempted a jump at the fountains in 1967, crashing and injuring himself so badly that he nearly died. Raha’s jump is fundamentally different — he’s going for height, not distance — but the point remains … this is dangerous stuff.

If anyone can hit the 100-foot mark and land the jump, it’s Colby … who won 13 X-Games medals, 7 of them being gold ones.

The epic stunt is all to celebrate the opening of the dayclub … and Colby says we shouldn’t be surprised if we see him hanging out there after he sets the record.

Colby assures us, “The OMNIA Dayclub will be going off. It’s like Rufus Du Sol and Martin Garrix, and I’m sure I’ll end up in there, but it’s a day club. It’s going to be at about 3 o’clock, so I’m sure I’ll round up with the family and close friends and my team, and we’ll go out and see what this town’s all about.”