I provide a sheet with templates in my CV carb kit if you wish to modify an Air Cleaner back by yourself. An original style Linkert AC back must have a special tab made, and welded on to support the carb's choke cable. A large piece of the AC back must be cut out, and replaced with a new patch, so that the (4) mounting holes, and the carb opening hole can be drilled, and cut to accommodate the Keihin carb. For a semi-skilled fabricator, this is not a difficult job. It takes me (3) hours to complete one. The picture below shows the area to cut out, and the placement for the choke tab.
For those who would like to save their original Linkert Air Cleaner Back, I offer a modified Keihin Air Cleaner Back from V-Twin Mfg. for $75.00. The picture below shows a modified "Original Style" on the left, and this "Back-Only" on the right. Originally, this new back has a strap across the front to support a large center mounting screw (which I remove), and I also have to weld-up a breather hole. I have to make, and install the (4) rivets to support the "J-Slot Indian Script" chrome cover that you are presently using. I also have to make and weld on a metal tab for mounting the carb's choke cable. It takes me (2) hours to modify one of these.
For those needing a complete Air Cleaner, I use a new "Reproduction" Indian Script unit, and then I modify the back (as shown above) for $155.00, including a foam filter element. Again, I recommend that you purchase the K&N Filter kit from Old Iron (www.oldiron.net).