Popping/Coughing noise from 1 cylinder (w/ video)

That makes sense. I've got no clearance on my exhaust valves with 250s in there. The only shims I could find that might work are 235s from Z1.

With 0 clearance it's hard to know if those will work. I'll find out when they arrive in a few days.

I managed to get my valve clearances set. Put the valve cover on, started the bike. I made some quick idle and pilot adjustments and the popping was gone.

Went for a short ride and about a half mile from home the engine started to race. I pulled over and was idling at about 3500 rpm. I adjusted the idle screw to bring it down and the popping came back.

I'm at a loss here. I can't find any air leaks. The carbs are clean. The carb holders are in good shape. The valves clearances are right. Air filter is new.

Is an air leak still the most likely culprit?

Forgot to mention, I also set the fuel levels and set the timing.

I haven't adjusted the needle height in the carb. Could that be it? They are both set the same and I believe they are both at their lowest setting.