((The Fonz (Henry Winkler) changed from a Triumph to a HD Knucklehead mid series 'Happy Days' - for more 'street cred'...)) OOPS! that was my impression NOT the facts!! - The ORIGINAL bike was the chopped Knucklehead but that bike was too much for Henry to handle, so they got him the smaller Triumph, he could sit on and push since he could not ride at all. He has tried but his dyslexia is SO bad he can’t process how to operate the brake, clutch and gears. All shots of him riding are staged.