What is wrong with my 1983 Honda vt750 that pops exhaust when you let off throttle?

Be certain that carbs are properly jetted, synched and adjusted. Removing the equalizer may affect mixture. It is possible to have hot unburned fuel from a rich idle mix to autoignite at the end of the muffler when it hits the air. Otherwise suspect stretched timing chains which result in slightly retarded cam timing, allowing unburned fuel into the exhaust.