It could be "clicking" for several reasons.
First, where is the "clicking" coming from?
Is it the small microswitch in the left brake lever clicking when you squeeze the lever to start the engine and nothing happens?
Does the clicking come from the engine area?
If you can be more specific then I can point you in the right direction.
What year is your bike? What mileage? Has any work been done on it that you're aware of?