Does it not have the same geometry as the Huret Eco? Those could handle a 28 tooth no bother as long as the jockey wheel cage was fitted in the correct hole. Many Eco's still going strong after all these years. But yes Shimano and Suntour were more sophisticated.
Lovely bike. I don't know if it's the angle of the camera but, in the first photo, the front fork looks a bit odd. Is this bike collection only or is postage offered?
Karma wheelset. Rear in good order with smooth bearings and running tru. Tyre appears undamaged. Front has a damaged rim, hub a bit notchy. Tyre appears undamaged. Collection from Glasgow.