Any suggestions? I don't know what else to do.
Adjust idle, high and low screws to make sure it is at least close to being tuned (See Mikuni Manual)
Change external fuel filter
Clean out small internal fuel filter inside carb
Clean carb thoroughly, blow out passages with compressed air
Check every inch of fuel lines and pulse line for cracks, brittle ends, bad connections
Bypass fuel selector to verify no air leak there
Fresh plugs gapped correctly
Test coil specs with ohm meter, wiggle wires to see if consistent, trim wires and replace terminals if needed
Check thoroughly for exhaust leaks, cracked water box, hose, bad connections
Verify tank check valve works right and installed properly
Swap CDI with "known good" CDI
Swap Stator with "known good"
These are basics I have tried, I have thought it was fixed after different things and then had the problem return. Good luck and report success if you find it. . .