I am new and i am troubled by rear cylinder

[maka_ca]

Hello Everyone
My name is Maxim.
I am regular reader of the forum - a lot of useful information is here. The forum saves me money, develops me mechanically, kills my spare time and finally become to my hobby.
I hope members of the forum help me to fix my motorcycle.
I will be short (too much text kills interest)

Patient:
1999 Honda Shadow VLX/VT600CD2
V-twin, single carburetor, vacuum fuel regulator, 4 gears.
All stock. 45000 km


Symptoms:
-Too rough on 1200-2500 rpm. When i start moving on motorcycle almost dying. Over 2500 rpm it is good. Works better on chock.
- When i suddenly turn throttle several times, motorcycle shoots in carb (i checked it with and without airfilter) and sometimes it dyes.
-Front sparking plugs black rear almost white/greyish
-Front and rear cylinders work under different rpms
-When unplug front Sparking Plugs rpms go down 400 rpm. When unplug rear SP rpms go down 200 rpm. => 200 rpm difference
-When unplug vacuum fuel regulator line from rear cylinder, idle rpms increase on 200 rpm (it means front and rear cylinders have the same rpms)
-When i unscrew bolts on intake manifold on rear cylinder and try imitate air leak - rpms increase on the same 200 rpm.
- If i turn throttle during test air leak motorcycle dyes.

Try to fix:
-Clean carburetor (take apart) in ultrasonic and blow by commercial air compressor.
-Check compression - 180 each cylinder.
-Check Air leak om intake manifold by brake cleaning fluid and propane - rpm did not changed.
-Check coils - the same voltage in (did not replace them)
-Check vacuum hoses/ gasoline hoses / petcock .
-Pilot screw in and out - did not help too much.
-Valves checked 3 times

Did not check:
-Timing

If you have ideas or had the same problem help me to resolve the problem
Thank you

[Monterey10]

I bet it's the carb. I really wonder if the fuel filters that Honda was using are doing the job. I've got a Spirit that has a plugged high speed jet.