Thanks, for reply. Actually tried google and couldn't come to exact conclusion. Yamah were not offer in stock from last couple of months so decided before opening i can know, so don't wanna leave bike at mechanic alone or relying them to get bearings for me if they put cheaper one.
Anyway got replaced by yamaha, and all in vain. Their wrong diagnose and poor mechanics, timing chain, tensioner and now bearings replaced but problem still there with more intensity even their engineers visited and checked.
Problem is ( very high noise in engine like rotational/friction sound plus sound of tappets which is constant always and loud like it is knocking .