I have to keep choke almost completely on to get it to start, runs a little bit and shuts off.

Out of adjustment and possible fuel flow issue I would think.

Hi,when starting bike you put the chock on,remeber this is to make a richer mixture for cold start,so when you start the bike put put the choke off a little bit as it warms up,other wise wat you are doing is couseing it to floud,so again as the bike warms up put the choke off little bit at a time,all the best.

Check the throttle position sensor. The fuel injector used for the choke is the only thing keeping the engine running. As soon as the engine warms up, the computer shuts off the injector causing the engine to starve.

If you need further help, reach me via phone at https://www.6ya.com/expert/scott_843b43f7ebebd3f5

Did you run a fine wire through all the carb orifices? I use a bristle from a wire brush.

clean the screen inside the muffler

It runs fast because the choke and or high idle are set. This is normal, after it warms up, give it a little gas and let off, it should idle down.

sounds like the carburetor has gummed up a bit, and may need adjustments - or, the fuel pickup in the tank has come loose [i.e.: deteriorated fuel lines] - also, make sure your gas mix is FRESH. if your gas mix is more than 2 months old, dump it

The Choke may be stuck or left on.

carb needs a clean , try fireing a bit of injector cleaner into the carb (remove airfilter and spray a little bit at a time !! then try again , if still no good the carb will need to come off and be cleaned ,
hope this helps
kind regards
bert31000

Make sure you have the propper mix of gasoline and oil. If the fuel is old mix new fuel to proper ratio. Find your manual and find the low speed fuel adjustment and the high speed fuel adjustment on the engine. First, turn the screws in and count the turns so you know where you started. Return the screws to the origional position. Usually 2 to 2-1/2 turns are a good starting point if you get them messed up. If the engine runs with the choke on you have to open the high speed jet a bit, 1/4 turn CCW. Keep trying this and get the feel of the change in the engine performance. If you have too much fuel the engine will not get to peak RPM. The low speed jet works similar but you have to adjust it so the engine idles at a decent RPM. This should get you on the path.