vfr/cbr rear conversion question

i just completed the front end of my f2 conversion. now moving to the rear end...i know there is a part that needs to be cut down...the i beam part. would one of you guys be so kind as to take a picture or give me an idea what needs to cut, grinded or changed for the back end to work. thank you

 

I guess you men the arm that hold the calipper as the stock brake disc is 256mm od and the cbr is 220mm od. You can get a brakdisc of a Hornet 900 its 240mm od, and it works whitout cutting the arm even if the brake pad dont grab 100 %. I used it for a few years, works ok, and look up the wheel.
The only problem is you have to take of the pads now and then to grind of the part that dont grab the disc as the pad dont wear there. If you dont do it it will stop working when the pads touch echother at some point.
Now I have shorted the arm.