I am on the tail end of my project and find I only have the chain guard for a 74 550 K and need one for a 77 550 F. The K mounts to two tabs on the swingarm and my F only has one. I just don't know what happens to parts people take off of bikes they are working on !!! I bought the two bikes as a project that someone else had taken apart and put in boxes. I would use the K guard and just weld another tab to the swingarm but I painted my frame and right now that would kill me. I am just looking for where the F guard mounts up to and I will make mine work until I can get the correct one at Vintage Days at Mid Ohio this summer. Looking for a picture or description of how it mounts. Thanks for the help.