RE: identifying cotton frames by Dani fink - written 01/11/2017 18:56:52


Hi Philip, as one of the rare cotton owners in switzerland I would like to help you. Until 1928 the frames where smaller (engines up to 550 sv, 350 ohv and smaler) , then they startet with the stronger model with the second toptubes less closer. Maybe a picture would help more. I collect Blackburne engines and bikes with  this engine inside.

philip butcher wrote (09/02/2014 19:11:04):


hello i have aquired a 1920/30s cotton frame with no visable  frame numbers to which i hope to fit a 500cc twin port jap engine, the frame and forks dont look as if they are large enough to take the engine /gearbox.               my question to the knowledgable owners is how many basic sizes of frames were avaliable and how to identify them ? i have a feeling that i have got a frame for a 250cc motor ? thanks in advance   philip