My 1999 honda shdow aero backfires on de acceleration.ihave changed plugs,coils &wires.

Backfiring on deceleration is air getting into the exhaust and igniting unburned fuel. You probably have an after market exhaust on. You need to seal up the exhaust system by replacing all the exhaust gaskets. Dig the copper crush washers out of the head and replace them with new copper crush washers. This should take care of most of the popping. If the problem persists,unbolt the fuel cut diaphragms from the side of the carburetors and inspect them for holes and stickiness. Replace the fuel cut diaphragms if they are bad . Fuel cut diaphragms are on almost all Honda Kei Hin carburetors to stop the cycles from popping or backfiring on deceleration With the stock exhaust.