The ones inside your actual starter. Sometimes the contacts inside the starter itself get crappy. They can be cleaned to a degree but if they are too worn or damaged, then they need to be replaced, if they can be replaced. It could very well be the battery. If the battery is too weak and cannot hold sufficient capacity, then as soon as you call for a demand of volts and amps, it will peter out and will not have enough ooomph to turn the engine over. It will have enough voltage to give you lights and whatnot seeing how they don't draw much amperage. I hate to see people just start changing parts for the sake of changing parts until the problem goes away. That is a waste of time and money. You can have the battery load tested and see if it is up to the job. If your charger does not supply a high amperage charge, and the battery is kaput, you still will not have enough to start the bike.
Check the surface charge of the battery, it should be over 12.5 volts. If you don't at least have that after charging it, you could have a bad battery/cell. If you have a good charge and it still won't start, run a jumper wire from the positive terminal on the battery to the relay terminal on the starter. Make sure your transmission is in neutral first or you will have another problem real quick. If the battery is good, and the starter is good, the motor should turn over. If that is the case, then your problem is relay, start switch, or a bad connection somewhere.