The HRC 28 swinger looks (at first measure) to be the same as stock. Haven't weighed it against stock yet though, but it does look ok in it's raw alloy state. Paul wants it but as they say, possession is 9/10ths of the law and all that.

The HRC frame was possibly a modified 21 frame. The one we had had the extra seat lugs welded on and then machined. The steering lock hole in the headstock was also machined in, not cast. Didn't have the huge headstock of the real F3 HRC 21 frame though.