Firstly thanks for the rundown of carb stripping and cleaning Viper. I stripped the carbs down and found that they were running the 120 jets on the right bank and 122 jets on left bank. Also the jetting needles were setup the same way the J51Bs were on the right bank and the J51As were on the left bank. There were no washers on the jetting needles. This bike was a Jap import with a full high flo exhaust system. The previous owner was a track day racer and supposedly had these "Jetted" by professionals. The air to fuel mixture screws were set to 2 1/2 turns roughly. One was over 3 turns from fully closed. As far as understand it whoever jetted it got mixed up. Instead of setting it up for front and back they set for left and right. Seems a lil strange to me maybe someone here can shed some light on the subject? Reason I took the carbs apart was that it was running somewhat uneven and firing the occasional fireball out the back end

I think you hit the nail on the head, i understand that it should be banked, back 2 and front 2. perhaps it was a friday afternoon job

Yep.

Front / Rear

If you have different sized jets (common) the larger ones go in the rears, they run slightly richer to compensate for the lack of cool air getting to them.

If you take the emulsion tubes out that the jets go into you may find you have ones with more holes in, if you do the ones with more holes go in the rears too (not sure about 30 carbs but NC24 deffo)

I think they came with 1 0.5mm shim as standard under the needles.

Have a read of Cammo's guide on here about over-hauling the carbs, he goes into detail about modding the slides for better throttle response.

The shims richen up the mid-range so after you have it all back together, if you find it's running lean (hole) in the mid-range raise the needles 0.5/1.0mm