I'm having some trouble setting up my carbs on my 97 F3 track bike. It has a mostly stock airbox with a paper filter, only mod is that the very front end was cut off to allow a pin stand. DAI solenoid delete, coolant lines to carbs bypassed, full race exhaust, HRC cams. The carbs have 40 pilot jets, 140 1 and 4 142 2 and 3. The problem is both at low RPMs as well as a burbley spot at 6k. It hangs at 3k for a few seconds then drops down when revved in neutral and stumbles under load at lower revs unless you goose it through. I originally thought the A/F was too lean at 1.5 turns so I put it to 2.5 and it got a little better but not much. It also pops on decel a little. Once over 6K it runs perfect but I can't always stay up there, sometimes I need to be at the lower RPMs. Carbs are spotless and synced, valves clearance is dead on, no air leaks. Compression is pretty even across all 4 at 185(a few PSI variation but nothing drastic). Plugs are dark like it's running rich but everything else is pointing to lean. I've had this thing apart so many times now and I'm wondering what I'm missing, it's probably something stupid. I'm at the end of my rope trying to figure this out and could use some help.