With the extra weight of the chain , sprocket and clutch the bike is heavier on that side.
Here is a little experiment to try ---
#1 take the cushions off of your couch and place them on either side of the bike
#2 place a level acrossed the frame tubes
#3 Let go of the bike , Which way did it fall ?
This is the heavy side and the tire will wear quicker on this side.
To remidy this problem you need to do one of two options.
#1 drill holes in the frame or engine plate on the heavy side to lighten it or
#2 pack the frame rails on the light side with sand, concrete or lead.
I have been doing this for years and my tires wear out dead even.
It makes wheelies effortless and staight as an arrow.