Audio problem: When Doc Hopper drives up to the town and some of the muppets are in the bus, Fozzie says "oh no" but it is Scooter's mouth that moves.
Audio problem: When Gonzo is flying over the countryside with the balloons, his mouth never moves during all his lines except "Ah this is the place to be. Whoopeeeeee!"
Plot hole: How did Professor Krassman get shocked into being a frog? The electronic device doesn't even touch his head.
Visible crew/equipment: As Miss Piggy jumps from the overhead platform onto the goons, the man that tossed her is briefly visible as he ducks down.
Answer: The closest thing to an answer is here, Martin Becker's obituary. His family states that it was a robotic Kermit on a bicycle. Outside of that, everyone else associated with the movie has been quiet on the subject.http://www.fridaythe13thfilms.com/saga/part5/martinbecker.html.
Rlvlk
They used gyros in the wheels - Martin Becker made the first self-driving bike for that movie-now the same tech is used in the self-driving bikes seen in the Netherlands. -Diana Becker, Martin's widow.