Visible crew/equipment: In the scene when Kermit confronts Doc Hopper he comes walking out of the bar. If you look at the top of Kermit's legs when he walks out, two pair of hands can be seen moving the legs.
Visible crew/equipment: In the scene where Kermit meets Fozzie, when Fozzie tosses the rubber chicken over his shoulder you can see Frank Oz's arm and where the glove ends.
Visible crew/equipment: When Kermit and Fozzie are driving to Hollywood, the reflection of the camera and the cameraman's hand are seen in the mirror.
Visible crew/equipment: When the Electric Mayhem Band has finished painting Kermit and Fozzie's car, you see the newly painted car and the band walks into the shot, you can see the head and hand of the puppeteer who is operating Scooter.
Visible crew/equipment: When Kermit is on his bike and enters the site of the Doc Hopper's Frog Legs Restaurant, look closely at the bike. You can see the wires moving the pedals of the bike; attached to the handlebars and behind the seat. Try to look for it when he rides by the black truck.
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.
Visible crew/equipment: As Kermit approaches the doors to see Lew Lord, the sleeve part of the puppet, as well as the top of the puppeteer's head can be seen.
Visible crew/equipment: As Fozzie, Kermit and Piggie chase after Gonzo, the camera vehicle is reflected on the nose of the car.
Visible crew/equipment: As Kermit is riding the bike, just before the scene transitions to him passing into town, there's a shadow of a boom arm that's guiding him on the ground behind him.
Visible crew/equipment: In the opening sequence, as the camera is in close up on Kermit playing the banjo, as he strums, the puppeteer's finger controlling the rod comes into the frame several times.
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.