Before starting the build:.

I decided to follow the recommendations  of several others I had read about on the RunRyder Century forums concerning the countershaft and cooling fan.  Some people have had problems with the countershaft spinning within its bearings and wearing a groove on the shaft itself. The solution seems to to loctite the bearing inner race to the shaft eliminating the initial clearance between the two pieces. This never lets the bearing begin spinning, and solves the potential problem. There have been a couple of other solutions that involve adding an extra bearing near the pinion gear, I decided to to follow the advise offered on the forum by a century field rep, and replace two small brass spacer washers with a second 5x13 bearing.  This required disassembling the upper frame halves, and removing a small lip that retains the single top bearing. Then removing the pinion gear and brass spacers. then slipping an extra bearing in place of the washers and reattaching the pinion gear. I will show the process in the pictures below, its easier than it sounds. I used an X-acto knife to remove the small lip.  And of course you will need a second 5x13 bearing  to add to the countershaft, it is a Century number CNBB1350.