If this bike has been sitting outside in the elements, you could have some corrosion on your electrical parts. Pull your stator cover off. Your pick-up coil is located at about 5:00 clock on your flywheel. You gonna need a flywheel puller to get flywheel off so you can clean inside. Check all wires. Clean nubs on outside off flywheel, these are what deliver spark to the pick-up coil. When you put everything back, set gap at .018 Also check ground as mentioned. At your ignition coil, check for fire at the two wires that plug in the coil(not spark plug wires)
These are some things you can check before throwing money at it. let us know