Good article Stuart!

The rod bearing wear is accelerated by the un-counterweighted crank flexing
in the center and edge loading the rod bearings as the rod journal is thrown
off perpendicular to the rod.

Counterweighting the crank keeps all the crank angles true, bearings last
longer (Often doubles bearing life), power increases, flywheel can be
lightened to increase acceleration and only adds about $150 to a WBX rebuild.

This is according to Gene Berg's tech articles.

My counterweighted WBX at 5800 rpm is smooth.

Robert