Most original parts of the router were left alone since they work satisfactorily.
The drive for the X-axis uses a single motor that drives two sprockets at either end of the gantry
There are two identical chain drives at either end of the gantry. The ensures that the gantry is driven squarely along the X-axis rails.
Will the same wear problem also develop on the x-axis rails. The answer is yes but the wear will happen more slowly.
There is a way to compensate for wear. The plate that is visible on top of X-Y floor is what is called a spoil board. It is a disposable piece of MDF where the router was used to mill the entire top such that the top is then aligned with the router’s travel both in the X and Y direction.
The chains for the X-axis are clamped at one end and tensioned ate the other end with an I-bolt.
The tensioning of the chains is important and critical for the proper motion in the X direction. Trial and error was used to set this correctly.
The ugly stuff in this picture is not part of the router.