That is not why you put the pistons in backwards. Stock type pistons have the pin offset slightly. This is to "push" the piston against the cyl wall, to quiet piston slap untill the pistons heat up and expand. This creates drag on the wall. By putting the piston on backwards, the cyl wall drag is reduced. Of course there is more piston slap, when the pistons are cold, but that does not hurt anything.
