i got the adjustable needles.. but i think they are the problem.
the shape is really different respect to the oem. they are much more conical, the oem are more similar to a cylinder, the conicity is low.
the oem also have the white plastic under the "circlip", this cause the little spring above to be better compressed, and the oem needle just look to be more stable, when you install it, it looks "maded" for it.
The aftermarket needle moves too much and looks really not made for this carbs. This is what i think.
In my life i rebuild a lot of carbs, and normally the needle is firmly positioned, and if you want to move it you must press it with a certain grade of decision, the aftermarket needle of my B12 looks loosen.
I was searching on this forum people that mounts the stage2 holeshot on a 2003 B12, for understand if this is normal but i found no people that gave me precise indications.
I found only lot of problems.
I think the gen 2 carbs are worst that gen 1.
So, this is what i do:
I cut the diaphram spring by 25mm, keeping the cuitted part upside
I install the new holeshot needles (4th groove from top with shim)
i istall the slow jet 17,5, (but the bike was rich as hell, so i come back to 15 at 3,5 turns out)
i install 147,5 main
I put pod filter
i check float bowls (i got the specific gauge)
I remove plastic tube between 1-2 and 3-4 carb
i try all combinations between screw and needle position, but now i'm tired to have my bike 90% of time spreaded around my garage. I want to drive it.