Check the earth lead that goes from the battery negative to the bike frame - it must be secure. If the solenoid is clicking then this is a good sign but check that the thick red cables (one to the battery, the other to the starter) are also secure. If no joy here, remove the starter motor from the bike, connect the main terminal to the battery positive and connect the body of the motor to the battery negative - if alls well the thing will spin.
John, March 2008