I am new to this site having recently acquired a SL175. I believe it to be a 1970 as it has the slotted muffler guard and frame Serial # 1017749, engine serial #SL175E-1017754. Right now it is for riding but hope to do a restoration at some point. the seat frame is cracked all the way across although the cover is in relatively good shape. I had a 1971 when I was a teenager and I don't remember the seat having a strap, but this one does. I am guessing the 1970 seat must have been different from the 71 and 72 or this one is not original. I purchased an SL 175 seat on ebay, but the brackets don't line up. Anyone have any ideas where I might find one that will fit? also needs turn signal lenses but the bike is otherwise relatively complete and runs like a dream.