Have you considered fitting a flat adapter plate for a bolt on silencer?
Other than that, i believe the pipe is 52mm, but I'm going back a few years.
Look to cut below the mid pipe silencer (two spot welds) if you want full noise / breathing ability.
Is there a silencer in the mid pipe, as well as the silencer can itself a_morti? Do you know of anyone who's cut one of these things open and taken detailed photos?
I'm interested in the dynsmics of modern motorcycle exhaust systems, and trying to figure out what aspects of their designs are for performance, and which are to comply with noise and emissions regulations.
They're all very heavy, so I'm guessing some aspects are also to make them robust enough to withstand impact with the road.
Other considerations are more obviously determined by cost and ease of manufacture, such as the horrendously ugly filler welding on the 4-1 link, and the choice of mild steel instead of stainless on the US Smurf models. The rotting that occurs on even relatively low milage bikes behind the headers/down pipes where they connect to the head is testimony to that.