I'm gonna throw in my 2 cents, i just did the mods and went for a little ride and found the same thing that the lower end was just as lean as before and i'm gonna change the pilot jet because that is where the lower end fuel is comming from not the needle or the main jet PN for #40 pilot is 92064-1108, i'll let you guys know if this helps the bottom end.
Carburetor setup as follows:
128 main
2.25 turnspilot jet
2nd position needle with n1tc
n1tc needle jet
slide drilled to 7/32ns
s-o two brothers

 

Ya let me know what ya find. Common problems i see.

 

i was playing with my idle jet with no easy finger jet in there, had to use a flat head bit, that was a boat load of fun, but it can be turned all the way out on idle and it uses all of the pilot which means when the transistion occurs between that off of idle and <4000 rpm its not getting enough gas but is efective enough to not have any transition problems, so i'm thinking a #40 may be too big, also with the stock 35 if you just hold it a little offof idle you'll notice that it doesnt run smooth, so the 35 is a little too small, but i'm still waiting for my pilot so just though i would add that.
not saying that the 35 is ok, you could, will help save gas, need to find out myself how bad the gas mpg has dropped.

carburetor running procecdure is as follows, but i could be wrong, this vaccu slide is kinda funny but usefull since kawasaki has used it for over a decade now.

pilot fuel screw is for idle, transition ports which feeds roughly from off of idle to about 4000 +-500rpm pilot, then from there depending how much vaccume you get from open throttle and speed of the engine determines how high the slide will open at that 4000 mark and up it feed from the pilot and the main jet, but mostly the main jet.

 

Stock pilot, 300 cc even, full DJ kit set up per instructions--flawless. Seemless from idle to WOT & when held anywhere in between.

 

I'm running a 40 pilot at around 300-1200ft above sea level, and it seems to work great. I am wondering if anyone has tried a 37.5 pilot, maybe this is the key for people in higher elevation? Just a thought.