To recline the seatback, lift the lever located on the outboard side of the seat, lean back and release the lever at the desired position. To return the seatback, lift the lever, lean forward and release the lever.

Rear Seat Release

WARNING!
Do not ride with the seatback reclined so that the shoulder belt is no longer resting against your chest.

In a collision you could slide under the seat belt, which could result in serious injury or death.