Rich Only on one Cylinder

Hi guys, maybe somebody has an idea (even though i feel this can't be fixed without an ECU flash)
I have a V2 Suzuki Intruder 1500cc bike, with sport exhaust straight pipe Cobra and now an K&N air filter. When it came it had a very rich condition on front cylinder and lean on back cylinder (sure it runs hotter) also it's an oil cooled bike only. Being straight piped O2/Lambda (wideband) is gone i guess this is the root of the problem.
Cleaned the injectors, synced throttle bodies checked, MAP sensor show good waveform, coils OK, injectors ok (not leaking, very small difference in fuel delivery qty, about 5% at idle). I did switched them to see if will make any difference and will scope them again (battery + starter died on the last diag), other sensors all ok.

Roughly, if nothing changes, i would be wrong if i asume this can;t be fixed without an ECU flash?

I attach a picture when bike came in and a picture after the injectors were cleaned and run idle in the shop pretty long time. It got better a bit, injectors were pretty dirty.

Actual problem of the bike is that after cold start, when fast idle closes the secondary throttle flies, it tends to die and idle drops around 700 rpm if i set idle to 1000 as Manual says should be 1000 rpm on idle, now with straight pipe and sport filter will idle ok at around 1200. Even so with idle at around 1200 still tends to drop around 900 and had to blip the throttle a couple of times after fast idle/choke closes.

Thanks