Mikuni Rs 34 tuning on KZ 1260

Hello I have a modified KZ 900 engine as follow: Welded Crank,Windage tray,MTC 1260 10:1 piston kit with buttons, ported head with titanium springs, 395 IN 380 Ex cams with Ape tensioner.
I have started the engine and it runs strong I noticed that middle is unstable so I suspected is lean, I have not taken it for log spins or anything just start the engine with 2 big fans for intervals of 01-15 mins and let Cool off.
pull out the spark and it confirmed my  suspicion the plug is whiter than brown signal of lean.
now the Carbs are RS 34 with velocity stacks, so since it has a gas pump that squirts I assume thats why all the RS series from 34 to 40 comes with the same size pilot 17.5 and recommender gas screw mixture is se yo only half turn.
so what should I do to enriched the mixture give more opening to the gas mixture screw like in intervals of quarter of turns? as I guess that increasing pilot size is not the practice in this carbs as I do with the VM series.
 

I inspected the carbs, had to do bench sync then changed the main to 150 , pilot still 17.5 had to open 3 turns the mixture screw but still stays ar 2000 Rpm or it stall complete don't hold idle, by the way your answers are been very helpful

I'm currently running 122.5 mains, and 25 pilots with 1.0 air jets.  The fuel screws are 1/8-1/4 turns out.  I may try 22.5 pilots, since she's a bit rich in this hot weather, and move the clip from #2 to the middle slot, and likely an air jet change too.

Hi thanks for the reply I wonder what size bore do you have? to have an idea of tuning? I Tried 20 pilots with 1 1/2 turns out in the gas mixture and rides very fast and scary with 2 turns out did not like it so max out was 1 1/2,  what I am still expiriencing is that when I start the engine it only holds idle around 2000 rpm if I try to adjust it down to lower the iddle the engine shut down.
I put 22.5 pilot with 1 1/2 mixture turn out and still holds idle at 2000 rpm if I try to adjust lower Rpm shut down, the needle only has 1 slot empty bellow the adjust washer. any input will be great

 

IMO, my KZ1100 is a weird concoction of subtle changes.  It has a 74mm. 1135 MTC piston kit designed for an 84 ZX1100A motor, and runs good on Regular pump gas. 
Somehow I managed to get the engine working ok initially without having it blow up in my face.  First off I got the engine to idle reasonably well by balancing the carbs.
My RS34 carbs are touchy to synchronize.  The slightest over-under adjustment creates significant detrimental effects.  For me it is primary to get the balance close with a manometer before making other carb adjustments.
The engine idles best with the pilot fuel screws less than a half-turn out.  That is what the tuning manual shows, and what seems to correlate with having the proper size pilot and air jets.
Start out with the needle clip in the middle slot, and double check that all the floats are set to 18mm +/-, and make sure there is no air leaking past the carb manifolds.
Not sure I can offer much further, other than to suggest making notes as changes are made..
 

Many different factors in selecting correct jetting, cylinder head flow, cams, cam timing, actual CR of engine, Timing ,what kind of condition engine in, fuel used in engine, air filters etc. best to start with stock & work on each circuit., me i would raise needle 1 notch and see what it does, you want to keep pilot as close to stock as possible.