new gsxr owner...carb troubles lol

[gsxr4001991]

hi all just got 1991 gsxr 400(my 1st bike ) its had carbs jetted and balanced supposedly, i got it cheap running on 3, i got new plugs n leads and she was purfect exept leaks from over flows , slow to idle after reving, and would cold start with zero choke/throttle. so i decided aha 'o' rings!!!!
so traced and sourced my own o rings as per tony sleeps measure ments.. but some r slightly different in my carbs pilot screws are not 3.5x1mm for example.
n e way i have rebuilt them several times now, pilot screw @1.5 (not sp coz no tps! and 32/33mm carbs) cable wound slack so butterflies r closed now my overflow problem in float boals sorted(o rings ther were dead!) bike now screams up2 about 4-6000rpm??? i have had them on the kitchen table about 8 times now maybee more!!!
after 1 rebuild i had her idling perfect but when i reved her a touch she screamed!!!!, it sound asif all 4 carbs are in sync tho when it revs up????i have checked am not catching throttle cable etc b/flies are closed an yet she seems to scream any ideas ppl cheers joe

[stripes1976]

try winding out your idle mix to 2 turns out then come back to me!!!

[gsxr4001991]

thanks for reading dude i already tried x2 turns and all he way in!!! exact same !!! i'm a alf decent car mechanic and have now read countless pages about thse mikuni's but am completely baffled now lol am clearly missing sumthing..even tried with throttle disconnected once to rule out snagging cable
ant tips/ideas appreciated ....knowing me its sumthing simple im overlooking!! have em on table now ...ill have another rebuild thur nyt
just to check...idle screws located bottom by float bowl with spring /washer/o ring? yes?...screw all the way into hole (lightly of coarse) then back out 1.5-2 turns correct???

[stripes1976]

yes mate. While your at it check for air leaks

[gsxr4001991]

ha ha yeah tha was ma next plan just got sum wd40 to find em!!! am just waitin for new bolts for the carbs !! bin very careful but them screws are dead so best wait