First off, Evel never got clearance to jump the Grand Canyon from the Department of the Interior. Instead, he attempted to jump the Snake River. In fact, it was his son, Robbie Knievel who finally jumped a portion of the Grand Canyon in 1999.
Second, the vehicle was never a "bike." The Skycycle-X-2 was more a super heated steam powered jet car or rocket vehicle with wheels than anything that could be construed as a "bike." That jump failed due to a parachute malfunction.