I just bought the same exact quad. It had the same exact problem. Poor idle and back firing. Your video helped out tremendously. Turns out that there was nothing wrong with my petcock. The vacuum line from the carb to the petcock got too hot and the vacuum collapsed the line. No vacuum no gas. The carb looked brand new but I took it apart anyway. The air/fuel screw was put together in the wrong order and I moved the clip on the main jet to the 3rd spot. Runs like a champ now. Thanks for the insight.

I got a quad master and this fixed mine same thing just fully automatic

I have this same atv and same issue. I’m wondering. Can I just plug both ends of the vacuum part, on the carb and petcock. And just run it on prime

If Intake boot is leaking could that cause a vacuum problem ?

Do you know how many quarts of oil this engine calls for?

do you know where the air fuel screw is

Poor old girls got the farts.

Do you still have this bike? I'll buy it. Or do you have any bikes right now that you're trying to sell?