vm28's sputter at 4k

i had this problem earlier. found the needles at the #1 slot. i put them at the #3 slot. runs ok for the first 5 minutes then starts to sputter badly at around 4-5k. also the transition from idle to main circuit is rough. the supply of fuel is good. my main jets are 120.0 i have the floats set to 24mm approx. its on my 1976 kz900, with a 1075 wiseco kit and performance cams. it seemed to run ok with the vm29's on it but had the same transition problem...and it seemed to load up too. any thoughts? my ignition system is factory coils with points.

ok. with needles at the #3 slot, plugs were black. i guess this is causing the sputtering. can there be that much of a difference between the #1 and #3 slots? goes from lean and sputtering to rich and sputtering? i will try #2 next, but i do not foresee an improvement.

OK... there really is insufficient info to help jet these carbs... Airbox? What type 28s? etc. I doubt the problem is jetting anyway. First, measure the power at your coils and second, are the valve clearances properly adjusted? Since the problem occurs using two sets of carbs, it really points elsewhere but the carbs could be contributing.

points and condenser will make them sooty black not the needle position.
carbs over fueling will make the plugs wet

points and condenser are the most ill adjusted detail next to low pressure in the tires

well, it has pods on it. the sputtering only occurs with the 28's (1974/75 variety). the problem with transition from idle to main circuit occurs on both. the plugs are not wet, just sooty. that is what i will check next. i have not done the mod and the wiring is factory. the points and condensers are new.