@hamikhan
@boldpisces
The thing i have experienced is GS engine is compatible with car oil's even one of my friend used his GS on ZIC X7 10W-40 that is API SN and his bike doesn't have any problem's whatsoever it is almost 45k km driven by now.
Try that to some Honda bike and you will face clutch issues for sure.
I tried using car oil's in my CD 70 back in 2012 and i ended up with burnt clutch plates just at 8k kms.
I don't know how Yamaha bike's will behave on car oil's have no experience with them.
So you can say that all bike's will behave differently on different oil's. It's also a thing of mental satisfaction.
Though one should try to stick to JASO MA/MA2 specific oil which are rated wit API SJ or later for motorcycles with wet clutches to be on safe side. If a oil is API SG or earlier that can even be used without JASO MA/MA2 rating. Oil's with API SJ,SL,SM,SN do have additional friction modifiers added to them which can mess up the wet clutch plates that's why one needs to check for JASO MA/MA2 specifications on that...