Carb tuning

Sometimes if you give the front accelerator pump arm more clearance it can help.
It gives the butter flys a chance to open up a little more before giving the shot of fuel.
Try to tighten the lock nut on the accelerator arm.
It makes the bolt that hits the pump arm a little shorter giving you more space between the arm and the bolt.
If this doesn't work i would try different pump cams.
Keep trying.
Once it's right, it will be worth it.