Having spent most of the day with fishing line hanging from various parts of the frame and along the length of the bike I am none the wiser. I have two lines along the length of the bike 140mm apart, these are weighted at each end and the width maintained by placing the line in slots 140mm apart. I then ensure the lines are parallel by using three centered vertical lines, one on the front of the engine one on the back of the engine and one from a cross member between the seat rails.
With the TZR wheel and swinging arm fitted there was a 5mm offset, I initially thought I could sort this by reducing the size of the brake caliper mount, however when I fitted a tyre to the wheel I realised that this would offset the wheel in the swinging arm making the tyre closer on one side than the other, that didn't seem right. The next thought was to machine the swinging arm to move it over to get the wheel alignment right. Before tackling this I decided to double check by putting the original swinging arm and wheel back in place to check alignment. Oddly enough the wheel is 5mm out !. So in conclusion either my technique for measuring the wheel alignment is wrong or the frame is bent. I have another frame I can check against its just a question of whether I want to spend even more time measuring. Still as the saying goes 'measure twice cut once' or in my case 'measure fifty times cut once'.