Reinstalling the front wheel

Putting the front wheel back on is pretty straightforward, with one exception: the speedometer drive. If you don't have the speedo drive aligned properly with the nubs on the fork (or more correctly, aligned just wrong), the slightest bit of torque on the axle nut will cause the wheel to be nigh on impossible to move.

First, take careful note of the bits and pieces that come off when you pull out the axle: axle, right-side spacer, speedo drive, washer, crown nut and cotter pin. Reassemble it all in the same order, ensuring that the speedo drive meshes with the teeth in the wheel.

The problem many people have is related to the rotational position of the speedo drive. The drive housing has two tabs on it, which are clearly meant to engage in two tabs molded into the lower fork housing. Unfortunately, the parts diagram doesn't really show this detail. If those tabs don't mesh correctly, extra pressure will be applied to the speedo drive housing, pressing it into the wheel. The extra friction should be quite noticeable.

The correct orientation is to have the tab on the speedo housing which is further from the cable attachment point set in between the fork's tabs.

Shown below are closeups of a correctly-installed speedo drive housing.