Hearing a sound like knocking

Please what is the job of this chain and what is called? Am hearing something like a knocking sound but my mechanic says it has to do with the clutch system and when he loosed the entire clutch basket, I noticed the chain is slacked. Please I need your assistance.

 

That chain drives the oil pump. You can see it here.
https://www.ronayers.com/oemparts/a/...l-pan-oil-pump

 

Hi Kiddo, welcome to the forum.
Please take a moment to introduce yourself.
Where are you from, how long have you been on two wheels, how many miles has the bike done, are you first owner etc.
We also love pictures.
What sort of knocking have you heard, when was this?
Cheers
Al

 

It's supposed to have a little slack.

 

mine has the exact same lay-out and knocks too.
You can reduce it by half by making sure you have an excellent quality of oil in it and replacing it minimal every year or 6000km
if you're living in a very warm climate, you might want to consider a slightly thicker oil.