Yar ye to phr app ki ghalti hay, brother... Agr buhat kum revs par app gear change krta hou, to is sa drivetrain par load prta hay, I think ye 'khrak' ya "grinding" ki si awaz clutch plates ke ghisnay (friction) se aa rahi hay...
Seems like you don't know how to shift properly.
They're a lot of videos regarding gear shifting on over Youtube... And also learn proper braking discipline on wet and dry pavement (road)... And there's another shifting technique called "Throttle Blip"which is great for bikes with dry clutches... Some people even use it on slipper clutches! This technique make down shifting silky smooth...
Good Day!