Vstar 1100 popping and backfiring on acceleration

yes

The primary cause for backfiring on deceleration is an air leak - if the baffles have been removed or modified or if the gaskets in the exhaust tract are not sealing properly, fresh air can be introduced into the exhaust stream causing a pop or backfire. Check your exhaust system - especially if you have recently had an oil change, since the pipe has to be removed to change the oil filter on this model.

The carburetors have air cut valves that should minimize popping. A lot of backfiring is caused by air leaking past bad gaskets. Try replacing the copper o-ring style crush gaskets where the pipe goes into the head. If the pipes are two piece replace the gaskets where the head pipe meets the muffler ( or make some using fiberglass cloth).

yes

Your bike is running lean (too much air and not enough fuel). What, if any, modifications have you done to the bike? If you changed the exhaust out for louder pipes, you need to adjust the f/a (fuel/air) mixture in the carburetor to compensate for more air going through the bike. Let me know here if you have made any type of mods to the bike.