1) take hose off carb and turn on petcock. Are you getting fuel? If yes, go to 2). If not, take petcock off tank and clean throroughly
2)Take carb off or turn sideways. Take bottom off. Remove main jet and pilot jet. Soak in carb cleaner. blow them clean. Look through them towards a light. Can you see clean hole all the way through them?? If so, proceed to step 3. If not, repeat step 2.
3) Reinstall jets. Turn carb back rightside up. Attach gas line. Turn on petcock. Is gas flowing out? Does the gas stop when you raise the float with your finger? If not, you need to remove float needle and seat and clean or replace. Also, measure float height at point where needle first contacts the seat when you raise the float. Set according to manual. (generally, the metal tang the floats attach to should be parallel to the bottom of the carb when you raise float up and needle touches the seat, but manual will give precise measurement). If all checks out, reassemble carb.
4) Put new spark plug in--brand new. Turn air screw in all the way, then back it out 1-1/2 to 2 turns. Turn on gas. Lean bike to left side about 10 seconds. Turn on choke. Do not touch the throttle--not one little bit. Kick bike over a few times.
5) Report back and let us know If it starts