re jetting help

hello everyone! first time posting long time reader. everyone here has been so helpful during my bike rebuild. let me tell you what i have and what my problem is.... i have a 1990 kz1000p cafe racer. i got this bike not running and have rebuilt the top end, re wired and fixed a few things here and there. the bike sounds great now however i am having an issue with it misfiring from the carbs. and you can feel the hesitation here and there. it seems that i have to have the idle way up and its just sucking down gas to keep it steady. i do have pod filters and i have just cut my exhaust off giving it about 6in of straight pipe. i welded two half washers staggered in the pipe for a little back pressure. it seems to be too lean (i haven't pulled the plugs yet)?? i have completely teared the carbs down and cleaned them but i am not sure if they were ever re jetted. from other posts it seems this might be my issue. any idea on what size jets i might need? thank you for all the help! this is my first project bike and its almost there i just want it running smooth so i can finally get out on the road with no issues.

If you cut the exhaust headers off 6 inches from the cylinder head the bike will never run smoothly.

its not 6 from the cylinder head its 6 after the bend cut just after where my peg is

That exhaust, pod filters and BS34 carburetor combo is not going to go well together. You will never be able to dial the BS34 crabs in with that setup. It will either be too rich at idle and to lean at speed or to lean at lower throttle settings and to rich at speed. The BS34 carbs do not have the adjustablity to make that setup work. I dumped a LOT of money and time into the BS34 carbs trying to get them to work on my modded GPz1100 engine and was never able to get them right. The amount of money I spent on the BS34's I could have bought a nice brand new set of Mikuni RS carbs, which is what I eventually did.