Do you regularly put your battery on a charger? If not your battery will become weak over time. A battery with low amperage may produce a clicking noise.
"- charge the battery if the motor fails to start or the starter relay makes a clicking noise
Because bike batteries are small, a lot of times they do not give advance warnings when they start to go bad. They can be fine one moment and dead the next. troubleshooting a battery can be difficult. Most people figure that just because a battery shows 12 volts on a multi-meter that it is fine. However, the resting voltage should not be below 12.2 volts."