Removed original voltage regulator and now it wont start

You are somehow on the wrong track. The regulator and the single wire going to it has nothing to do with cranking. You may be wiggling the harness and upsetting a poor/ loose splice or something like that. You need to get a light/ meter and make some tests

Is this auto or stick? What exactly does it do/ not do?

Does the starter crank? Cranks but no spark? Does not crank at all?

Does this appear to be factory wiring?

This could be a damaged bulkhead connector, and you moved things just enough to "break" a connection.