help with carb tuning , please!!!

[Dave223]

ok guys, Im totally new at 2 strokes, and I need all the help I can get!
I finally took the 84 out for a test run, with only front brakes. Anyhow, it takes off like a rocket, but after 1/2 throttle, it bogs really bad like its flooding out. It also smokes BAD when I take off, and has the telltale drip of oil from the exhaust. I checked a new plug and its coming out wet and oily black.
Now the fun part, the engine used to have a 300 kit on it, but the previous owner burned the piston. He put together the engine I have now bored .20 over, with what appears to be a stock pipe. The kicker is, he used the carb for the 300. All I can find out from the carb is that its a Mikuni, one one side it says KOGYO and the other side says JAPAN. I searched when I cleaned out the carb and couldnt find any numbers. I measured the outside of the throat where the filter would go..its 2 1/2"s on the o.d. I havent measured it but compared to a 200 or 185, the slide is HUGE!!!
Thats all I know about this carb at this time. Now for the questions:
1 what is the jet sizes for a stock carb on an 84 R?
2 with just the info on the carb that I have, how do I go about getting jets for it? Do jets for Mikuni carbs interchange? Like, can I order a jet kit or jets from Dennis Kirk for a Mikuni?
3 will raising or lowering the clip on the needle help me at all? will it affect idle?
4 what would be a good starting point for jets (sizes)?
5 how would you go about setting this up?
Below are a few pics I have of the carb, on the filter side of it, at the top is some sort of needle with a hose running from the lower side of the float bowl. Is this a "dial-a-jet"? and should I leave it or? Thanks for the help, Dave

[82300R]

when i got my 81 250r it did not have a silencer or a airbox on it . i only rode it like that once or twice briefly. it seemed to run fine other than very loud naturally. well i get a silencer ,air box, new filter put them on . well thats what mine was doing, started and ran fine slow but bogged bad at half to full throttle. i just kept messing with the air screw and idle and cleaning the plug as needed till i got it right. runs and idles fine now. that may help you ,i don't know. oh yeah had to change the plug a few times also.