[NinjaBraap]

If this is still an issue for you, here's a couple suggestions.

1. check your intake boots on both side of the carbs. Spray soapy water and see if it bubbles, that'll tell you if your boots are cracking, causing a vacuum leak. You can do this to all of your vacuum lines on the carburetor as well.

2. check your diaphragms, make sure they are in good condition and intact. There's an air cutoff diaphragm on the carb as well that gets dirty, take it out, clean the housing, make sure the diaphragm itself is intact and clean.

If it's still happening after all that, just rebuild the entire carburetor. Soak all metal parts is carb cleaner or fuel, replace all rubber gaskets and diaphragms, replace the float needle and mixture needle, get new jets if necessary, start fresh.

It could be something as simple too as the intake boots not being all the way on or the clamps not tightened enough.