I'd also like to show my modified clock, since it's kinda the heart of the serializer;
The base clock runs constantly. The enable signal gets written to the register on the next rising edge of the clock. The register output is AND-ed with the base clock output. This ensures the clock always has a consistent output when being enabled, as the enable signal can't make the output pulse prematurely.
The F0 and F1 signals control the frequency of the clock.