help me tune please

I thought I was done. but after all new wheel bearings, head bearings, rebuilt forks, carb clean, sparkplugs, throttle and clutch cable, my bike still needs some love. actually just the engine. it backfires there is almost no power when I jam the throttle (it rode much better with a gummed up carb) I replaced the jets with stock jets. rpm jumps up and takes a long time to come down. the carbs are all out of sync, and when I put it into 1st from nutral a horrible grinding noise screams out (clutch basket?). Are these running problems (clutch not included) due to the bike running lean? if so its probly from my airfilter which probly isnt seated on the box. how many turns are the factory fuel screws supposed to be out? mabe the PO messed with them in an attempt to make the bike work without rebuilding the carbs? thanks. I am so close to getting it done I love this bike!!!!!!

 

-float levels need to be checked using a clear tube and fuel, and adjusted if necessary.

-carbs need to be bench-sync'ed before they go back on the bike.

-before disturbing the mixture screws make notes of what position (how many turns out) each one is in NOW.

 

In addition to bigfitz's pointers:
rpms coming down slow sounds like balancing issues. Start with a proper bench sync and go from there. Could be the new throttle cable is routed the wrong way or is kinda sticky, make sure the cable doesn't hold open the butterflies.
Grinding noise when putting in first. Did this occure before swapping clutch cable? If not the cable isn't properly disengaging the clutch, tighten the cable till there's about 3mm of slack in the lever.
For the f actory fuel screws, a starting point of 2 3/4 to 3 turns out seems to be the tried and proven starting point.