Continuity mistake: In the outer office, as the secretary begins to sneeze, the fan is already on. Kermit then goes to turn on the fan to blew animal dander at her. Also, as they make noise, Kermit is heard talking, but his mouth doesn't move.
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.
Continuity mistake: As Kermit faces Hopper, there's a large black square behind Kermit, between Fozzie and Doctor Teeth that only appears in the long shot.
Visible crew/equipment: As Fozzie, Kermit and Piggie chase after Gonzo, the camera vehicle is reflected on the nose of the car.
Continuity mistake: When the duo stop at the church, the wording on the sign is either shaded or dingy. But a moment later when they go to get out of the car, the sign's lettering is clean and bright.
Continuity mistake: As Kermit and Fozzie stop at the Frog Legs billboard, it's easy to see that it's out in the wide open. but when the "Myth, Myth" gag is used, there's suddenly trees directly behind it, where the lady pops out saying "Yes?"
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.
Continuity mistake: In the close ups of Kermit playing the banjo, his arm moves, and when in wide shot, only his hand moves over the strings.
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.
Other mistake: As Fozzie corrects the car to keep from crashing, watch the two of them in the long shot by the church. They are bouncing very rapidly as they come to a stop, suggesting the film was sped up. Also, Fozzie looks to the left of the steering wheel to shift gears, rather than the right, where the shifter would be, on the transmission hump.
Continuity mistake: As Hopper asks Kermit about being rich and famous, he goes to stroke the back of Kermit's head. As the angle changes, Hopper's hand is under Kermit's chin.
Continuity mistake: When Kermit and Fozzie meet Big Bird, their car stops about fifteen feet behind him, at the end of some dark tire tracks. But when the camera looks at the pair in the car, they're looking directly at their left, and Big Bird converses with them looking to his left in quarter profile to them. When they leave, their position is about ten feet back from the end of the marks, a good twenty feet from where they originally stopped.
Other mistake: When Fozzie backs his car into Hopper's and then leaves, the front of the Caddy shows no damage, despite the severity of the hit. Not even a speck of paint on the bumper.
Factual error: The TV remotes of the day wouldn't control more than one TV at a time, yet they all come on and go off at the same rime.
Continuity mistake: After Kermit is tossed over the crowd in the El Sleazo, he catches on a ceiling fan, and it swings a bit from the impact. After a shot of the bartender speeding up the fan, it is no longer swinging. This is impossible with any weight on one blade. When Kermit is slung off the fan, you can see the fan is not on at all, Kermit is at the piano, and just about everybody in the place is still looking at the fan.
Revealing mistake: In the scene where Kermit and Miss Piggy are having dinner, you can see a square outline around the moon.
Continuity mistake: The crack in Fozzie's Studebaker windshield comes and goes throughout the film.
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.