Have to look a few few things. First you want to take your carb to defaults. Go flush on the low speed needle and 3 1/2 turns out on high speed. set the idle so that the carb is open at least 1.5mm. Then make sure you are primed. Is fuel getting to the carb? When you tug on the pull start, do you get resistence? If not, you have a lack of compression, which means you need to check for an air leak or your piston and sleeve need to be replaced. after tugging on it for a while, pull the plug and turn the truck upside down and pull the starter a few times. Did fuel come out? If not, you are not getting fuel in the engine. You may also need to see if the clutch is good. Set the truck on a block of wood so the the wheels aren't touching the ground. When you try to start, do the wheels spin? If they do your clutch is whacked. Does the enigine even sputter? If you can get it that far, you aren't far from getting it running, it just may take some adjustments. Maybe just a slightly higher idle.