Looking for help with motorcycle troubleshooting.

I recently completed a build that is a 1982 Suzuki GS850GL and it starts perfect every time and at high RPM it runs smooth and it seems very fast.. The problem I am having is at low RPM there is a lot of hesitation in the throttle until you get up to the higher rpms.It has even died several times on takeoff like there isn't enough power, it sounds noticeably different as well, as if it is struggling.The carbs were professionally cleaned/rebuilt/and tuned.Any ideas on what to check first, my initial thoughts were carb tuning or timing but the fact that it runs so well at higher rpms is really confusing.Thank you! via /r/CafeRacers https://www.reddit.com/r/CafeRacers/comments/blvtdn/looking_for_help_with_motorcycle_troubleshooting/?utm_source=ifttt