My friend first of all I would like to tell u a little bit about this bike,
I went to visit Suzuki swan showroom to buy his bike and I found how pathetic the metal quality of this bike is,
It looked like it was made by our local kharadiaas,
Now coming back to ur problem,
I would suggest u to use havoline or liqui moly oil for a try
To soften the differential operation,
Which may help u in terms of noise reduction..
Comin back to the last part of my story,
I went to murres road and bought my self a deluxe 125 and am very pleased with overall ride of this Honda bike.