odd noise from engine

[weazelz]

the engine on my friend's curvy is making a rather odd noise. at idle it make a kind of tapping noise - almost liek metal slapping on metal. it's not in time with the noise of the engine, but there'll be a noise every second or so, but not in any discernable pattern. not terribly loud & it seems to go away above ~1500 rpm

any ideas? I have a few thoughts, but I don't want to prejudice the response with my unfounded speculation ;-)

~andy

[BILLY]

Cam chain mabe?

[Blazingsvbiker]

hes ****ing up hes engine cause of riding without oil (and the waring light never cleared up?)

[Blue_SV650S]

Cam chain mabe?

Seconded

Might be a sticky tensioner device.