when I start to accelerate, the engine starts to fail

Hello, my 1997 softail starts flawless with the kickstart or electric motor. while standing still there is no problem.
when I start to accelerate, the engine starts to fail, backfires and isolates the sparking plugs ... it loses power and shuts down.
I have a new rectifier, new batery, 1 year old ignition, new coil, new cables and new plugs ...
Someone can help me?

Sounds like carb accelerator pump not squirting gas down carb throat, pull airfilter and look into carb while working throttle (engine not running), should see stream of gas. If not pull float bowl and check circuit. Severely leaking manifold boots might be contributing