Valve stackers with warm engine ZX9

Hello, with warm Mptor you can hear a speed-dependent tacker at my 02 ZX9, I type valves or the control chain. At the Sa I would like to open the valve cover, but I have not looked at the engine yet, I have to pay attention to something special! Tank and covering should be enough to remove the lid? How tight must the chain be stretched? Greeting Bimo