Three teenagers are in hospital after a bike stunt went horribly wrong in Adelaide yesterday.

The two boys and a girl were attempting the ‘jump through fire’ stunt at Findon Ski Kids yesterday afternoon.

The flaming cardboard was meant to break up and instead stuck to the 15-year-olds as they rode through.

Spectators were shocked to see all three on fire before the flames were doused by onlookers.

They were all wearing protective clothing including overalls, goggles, helmets and balaclavas however still suffered burns.

They were treated ambulance crews before being taken to Women’s and Children’s Hospital.

St John Ambulance crews treated the riders before SA Ambulance crews arrived and took the trio to the Women's and Children's Hospital.

It’s believed the accident occurred due to incorrect preparation. The cardboard wasn’t cut properly and when the teens hit it, it didn’t break as it was supposed to.

Organisers say it’s a stunt that they’ve performed plenty of times but it was the first time these riders had attempted the jump.