Vz 800 idles wont rev just stalls

Sounds like you need to do a carb clean out sounds like some debris is blocking the fuel supply gas tank could have some garbage in there also

Clean carb and air
mix screw needs set and rev screw

Hello
I would start with the easy less expensive stuff first.
Check/Replace your spark plugs. Carbon fouled, sooty plugs don't like to idle.
Clean/Change your airfilter. Dirty air filters choke the motor. choked motors either stall or rev high.
Carburetor idle screw needs set.
that is adjusted after the bike is warmed up to operating temperature, then set idle.
If that doesn't have you cleared up then you'll need to have your carbs cleaned.

Have a great weekend
Big Al

you need to clean your carb

Sounds as if your bike needs a good tune up, until you do it, you could turn up the idle screw a tad and that will stop stalling at low speeds, but not cure your problem. Get your self a good manual and if you feel you are up to it, do it yourself, else find a good bike mechanic.

The Choke may be stuck or left on.

Hi I am Vortash sounds like an inlet manifold air leak or check the ignition leads they could be sparking out to earth , or possibly the choke is stuck on or filter needs changing restricting air flow .. Hope this is of help regards Vortash

check your transmission fluid,the motor will stall when fluid is low