Odd noise at idle

[mixongw]

Odd in the sense of when it occurs. It goes like this... tap-tap (about two seconds elapse) tap-tap (two more seconds) tap-tap, repeat. It sounds like a valve tapping noise. I believe it's coming from the cam/valve area. It only happens at idle. Any rpm above idle, even slight, causes the noise to go away.

[1980GS1000E]

Could be the fuel petcock.

[psyguy]

camshaft end float noise?
(do a search on the bikecliff website, theres a good article there)

[chiphead]

I'll bet you a cup of coffee or an ice cold beer if you do a GOOD carb synch the noise will go away.

[rudy]

I'll bet you a cup of coffee or an ice cold beer if you do a GOOD carb synch the noise will go away.

I've heard of that making clickity noises too. Would be a good place to start. Don't need to tear anything apart either, at least just to check it.