This achievement is pretty simple and can be done in multiple place throughout the game. There's a couple of ways to fully break your bones and smash up your bike. One being falling from a massive height, so a jump or the other is to drive into some explosives scattered about the tracks. Out of the two choices, the explosive route is the easiest as you don't have to worry about the speed, the jump or height of your driver when trying to gain this. Simply falling or driving into the explosive will do the job.
The first and best place to try this is on the Roller Coaster track under the Terminal Velocity event. From the start, just follow the track and don't worry about anything. Once you come to the massive drop down with the section where you go through the water, you'll need to slow down just after this.
Once you've passed this, you'll go through one checkpoint and make sure you follow the lower route. Following that will take you to the ground side of the track and another checkpoint which is right next to a jump and some water. If you look in the water you'll see some explosive barrels.
So from the checkpoint, simply fall off the ramp and into the water. The barrels explode automatically, so you don't have to aim for one. Once everything goes off, the achievement will unlock.