Hey guys and gals
I'm stumped and having issues. Hopefully someone can help. My gf has a 2000 cbr f4(carb) we have had the carbs cleaned and jetted with it running an aftermarket slip on exhaust and a knn filter. When the thing gets warm at idle it dies out slowly over say a minute of time. Any clue what may be causing this? Replaced a battery and rectifier and stator already. Carbs was synced. I'm pretty sure it's carb related somewhere but idk where. I've tried adjusting the af ratio screw several different ways on each carb and about every possible combination also. If I remove a vacuum line on #1 and 4 carb the idle increases and it idles fine but giving it throttle with them off it hangs at higher rpms.. I'm pretty new to this sort of thing and idk I'm out of ideas. Anything would help. Thank you in advance.

 

In a sense, you answered your own question. When you induce more air into the system, it runs better. That indicates the fuel/air mixture is incorrect.
Assuming all the work cleaning and syncing the carbs was done correctly, what variable does that leave?
When the K&N pods were installed, it reduced the amount of air that can enter the system. Because of this the jet sizes should be reduced to lessen the amount of fuel. Right now you are running too rich I would imagine.