What I found that works is start at the gas tank and work your way down to the carb. Take the tank off and fully clean it. I drain the gas. Put some fresh clean gas in there , swish it around and drain. Pull the petcock off and again clean the inside of the tank with carb cleaner spray and let it drain out the holes where the petcock goes .I even sprayed all the inside of the tank out with a nozzle from the compressor. Then literally clean the fuel line and the filters on the petcock then reinstall.Remember you cant get these things too clean. Now the carb, pull the bowl off and the float and the 2 jets. The pilot jet is the shorter fatter one and the needle is the skinny longer one. Check to see if you can see through them. The hole when clean is small so make sure it is super clean. I usually let the jets sit in carb cleaner for about 15-30 mins. Clean the entire body of the carb every orifice ,inside and outside.Make sure you also pull out the Pilot jet and needle jet screws also and put them back exactly the way they came out. This is very important.If you need new gaskets replace them as they are cheap .Slap it back together and it should run fine if you cleaned it really good.Now here is the kicker The pilot jet is only a 12.5 on this thing and gas goes bad so fast these days.So there is a screw on the side of the bowl at the bottom.If you are done riding it on your trip out. Back that screw out and drain the carb and this problem will never happen again. These little jets are so small making them so sensitive to any dirt that gets in there. I drain the 50 all the time and if I wont be using it for an extended amount of time I drain the gas and put new fresh fuel in when we use it again it fires right up. I hope this helps.