Pull the float bowls and check to see if the needle is stuck. You might also see some crud in the bowls that can be cleaned. Make sure you use a good quality Philips screw driver if the screws haven't been replaced with Allen head ones. Since the tank is off, you could try forcing a bit of compressed air into the fuel line inlets to the carbs to help force any stuck needle valve off the seat.
Edit - just noticed you already have done this so...
Last edited by Gregger; 04/19/2021 7:16 PM.
