Strange noise.

Hello CB 500 mates, by almost a week I noticed a noise and I cannot say where exactly comes from. It goes like this. I start the bike, engaging the first gear and when I'm releasing the clutch lever, almost at the point where the bike is starting to move I hear a single "cluck!" noise...the intensity is not so big but is noticeable. I figured that the noise comes from the left side of the bike somewhere nearby the attack sprocket and shifting gear lever...the odd thing is that this noise doesn't appear every time I use the bike. I was thinking to check the attack sprocket to see if it's well bolted or is having a free play... Any other suggestions?

Slack chain? Check it's not too loose.

If it is, when you move it takes up the slack and makes a clacking noise.

Last time I checked the chain it was in normal operating conditions...I might check it again those days.