The gearbox casing on this bike is an extra
strong one by Cal
products, the bottom is shaped so it fits in the rectangular
openings in the transmission plate. This allows the gearbox
to move in a straight line only, so the belt is always aligned
correctly. This casing also has a threaded boss for an adjuster
screw so I modified the transmission plate by welding on a 3/8"
strip. Now adjusting the belt will be a lot faster and easier!